GCP Templates for C4 Diagrams using PlantUML

I am a believer in the mantra of “Everything-as-Code”, this includes diagrams and other architectural artefacts. Enter PlantUML…

PlantUML

PlantUML is an open-source tool which allows users to create UML diagrams from an intuitive DSL (Domain Specific Language). PlantUML is built on top of Graphviz and enables software architects and designers to use code to create Sequence Diagrams, Use Case Diagrams, Class Diagrams, State and Activity Diagrams and much more.

C4 Diagrams

PlantUML can be extended to support the C4 model for visualising software architecture. Which describes software in different layers including Context, Container, Component and Code diagrams.

GCP Architecture Diagramming using C4

PlantUML and C4 can be used to produce cloud architectures, there are official libraries available through PlantUML for Azure and AWS service icons, however these do not exist for GCP yet. There are several open source libraries available, however I have made an attempt to simplify the implementation.

The code below can be used to generate a C4 diagram describing a GCP architecture including official GCP service icons:

@startuml
!define GCPPuml https://raw.githubusercontent.com/gamma-data/GCP-C4-PlantUML/master/templates

!includeurl GCPPuml/C4_Context.puml
!includeurl GCPPuml/C4_Component.puml
!includeurl GCPPuml/C4_Container.puml
!includeurl GCPPuml/GCPC4Integration.puml
!includeurl GCPPuml/GCPCommon.puml

!includeurl GCPPuml/Networking/CloudDNS.puml
!includeurl GCPPuml/Networking/CloudLoadBalancing.puml
!includeurl GCPPuml/Compute/ComputeEngine.puml
!includeurl GCPPuml/Storage/CloudStorage.puml
!includeurl GCPPuml/Databases/CloudSQL.puml

title Sample C4 Diagram with GCP Icons

Person(publisher, "Publisher")
System_Ext(device, "User")

Boundary(gcp,"gcp-project") {
  CloudDNS(dns, "Managed Zone", "Cloud DNS")
  CloudLoadBalancing(lb, "L7 Load Balancer", "Cloud Load Balancing")
  CloudStorage(bucket, "Static Content Bucket", "Cloud Storage")
  Boundary(region, "gcp-region") {
    Boundary(zonea, "zone a") {
      ComputeEngine(gcea, "Content Server", "Compute Engine")
      CloudSQL(csqla, "Dynamic Content", "Cloud SQL")
    }
    Boundary(zoneb, "zone b") {
      ComputeEngine(gceb, "Content Server", "Compute Engine")
      CloudSQL(csqlb, "Dynamic Content\n(Read Replica)", "Cloud SQL")
    }
  }
}

Rel(device, dns, "resolves name")
Rel(device, lb, "makes request")
Rel(lb, gcea, "routes request")
Rel(lb, gceb, "routes request")
Rel(gcea, bucket, "get static content")
Rel(gceb, bucket, "get static content")
Rel(gcea, csqla, "get dynamic content")
Rel(gceb, csqla, "get dynamic content")
Rel(csqla, csqlb, "replication")
Rel(publisher,bucket,"publish static content")

@enduml

The preceding code generates the diagram below:

Additional services can be added and used in your diagrams by adding them to your includes, such as:

!includeurl GCPPuml/DataAnalytics/BigQuery.puml
!includeurl GCPPuml/DataAnalytics/CloudDataflow.puml
!includeurl GCPPuml/AIandMachineLearning/AIHub.puml
!includeurl GCPPuml/AIandMachineLearning/CloudAutoML.puml
!includeurl GCPPuml/DeveloperTools/CloudBuild.puml
!includeurl GCPPuml/HybridandMultiCloud/Stackdriver.puml
!includeurl GCPPuml/InternetofThings/CloudIoTCore.puml
!includeurl GCPPuml/Migration/TransferAppliance.puml
!includeurl GCPPuml/Security/CloudIAM.puml
' and more…

The complete template library is available at:

https://github.com/gamma-data/GCP-C4-PlantUML

Automated GCS Object Scanning Using DLP with Notifications Using Slack

This is a follow up to a previous blog, Google Cloud Storage Object Notifications using Slack in which we used Slack to notify us of new objects being uploaded to GCS.

In this article we will take things a step further, where uploading an object to a GCS bucket will trigger a DLP inspection of the object and if any preconfigured info types (such as credit card numbers or API credentials) are present in the object, a Slack notification will be generated.

As DLP scans are “jobs”, meaning they run asynchronously, we will need to trigger scans and inspect results using two separate Cloud Functions (one for triggering a scan [gcs-dlp-scan-trigger] and one for inspecting the results of the scan [gcs-dlp-evaluate-results]) and a Cloud PubSub topic [dlp-scan-topic] which is used to hold the reference to the DLP job.

The process is described using the sequence diagram below:

The Code

The gcs-dlp-scan-trigger Cloud Function fires when a new object is created in a specified GCS bucket. This function configures the DLP scan to be executed, including the DLP info types (for instance CREDIT_CARD_NUMBER, EMAIL_ADDRESS, ETHNIC_GROUP, PHONE_NUMBER, etc) a and likelihood of that info type existing (for instance LIKELY). DLP scans determine the probability of an info type occurring in the data, they do not scan every object in its entirety as this would be too expensive.

The primary function executed in the gcs-dlp-scan-trigger Cloud Function is named inspect_gcs_file. This function configures and submits the DLP job, supplying a PubSub topic to which the DLP Job Name will be written, the code for the inspect_gcs_file is shown here:

At this stage the DLP job is created an running asynchronously, the next Cloud Function, gcs-dlp-evaluate-results, fires when a message is sent to the PubSub topic defined in the DLP job. The gcs-dlp-evaluate-results reads the DLP Job Name from the PubSub topic, connects to the DLP service and queries the job status, when the job is complete, this function checks the results of the scan, if the min_likliehood threshold is met for any of the specified info types, a Slack message is generated. The code for the main method in the gcs-dlp-evaluate-results function is shown here:

Finally, a Slack webhook is used to send the message to a specified Slack channel in a workspace, this is done using the send_slack_notification function shown here:

An example Slack message is shown here:

839Slack Notification for Sensitive Data Detected in a Newly Created GCS Object

Full source code can be found at: https://github.com/gamma-data/automated-gcs-object-scanning-using-dlp-with-notifications-using-slack

Forseti Terraform Validator: Enforcing resource policy compliance in your CI pipeline

Terraform is a powerful tool for managing your Infrastructure as Code. Declare your resources once, define their variables per environment and sleep easy knowing your CI pipeline will take care of the rest.

But… one night you wake up in a sweat. The details are fuzzy but you were browsing your favourite cloud provider’s console – probably GCP 😉 – and thought you saw a bucket had been created outside of your allowed locations! Maybe it even had risky access controls.

You go brush it off and try to fall back to sleep, but you can’t quite push the thought from your mind that somewhere in all that Terraform code, someone could be declaring resources in unapproved locations, and your CICD pipeline would do nothing to stop it. Oh the regulatory implications.

Enter Terraform Validator by Forseti

Terraform Validator by Forseti allows you to declare your Policy as Code, check compliance of your Terraform plans against said Policy, and automatically fail violating plans in a CI step. All without setting up servers or agents.

You’re going to learn how to enforce policy on GCP resources like BigQuery, IAM, networks, MySQL, Google Kubernetes Engine (GKE) and more. If you’re particularly crafty, you may be able to go beyond GCP.

Forseti’s suite of solutions are GCP focused and allow a wide range of live config validation, monitoring and more using the Policy Library we’re going to set up. These additional capabilities require additional infrastructure. But we’re going one step at a time, starting with enforcing policy during deployment.

Getting Started

Let’s assume you already have an established CICD pipeline that uses Terraform, or that you are content to validate your Terraform plans locally for now. In that case, we need just two things:

  1. A Policy Library
  2. Terraform Validator

It’s that simple! No new servers, agents, firewall rules, extra service accounts or other nonsense. Just add Policy Library, the Validator tool and you can enforce policy on your Terraform deployments.

We’re going to tinker with some existing GCP-focused sample policies (aka Constraints) that Forseti makes available. These samples cover a wide range of resources and use cases, so it is easy to adjust what’s provided to define your own Constraints.

Policy Library

First let’s open up some of Forseti’s pre-defined constraints. We’ll copy them into our own Git repository and adjust to create policies that match our needs. Repeatable and configurable – that’s Policy as Code at work.

Concepts

In the world of Forseti and in particular Terraform Validator, Policies are defined and understood via easy to read YAML files known as Constraints

There is just enough information in a Constraint file for to make clear its purpose and effect, and by tinkering lightly with a pre-written Constraint you can achieve a lot without looking too deeply into the inner workings . But there’s more happening than meets the eye.

Constraints are built on Templates – which are like forms with some extra bits waiting to be completed to make a Constraint. Except there’s a lot more hidden away that’s pretty cool if you want to understand it.

Think of a Template as a ‘Class’ in the OOP sense, and of a Constraint as an instantiated Template with all the key attributes defined.

E.g. A generic Template for policy on bucket locations and a Constraint to specify which locations are relevant in a given instance. Again, buckets and locations are just the basic example – the potential applications are far greater.

Now the real magic is that just like a ‘Class’, a Template contains logic that makes everything abstracted away in the Constraint possible. Templates contain inline Rego (ray-go), borrowed lovingly by Forseti from the Open Policy Agent (OPA) team.

Learn more about Rego and OPA here to understand the relationship to our Terraform Validator.

But let’s begin.

Set up your Policies

Create your Policy Library repository

Create your Policy Library repository by cloning https://github.com/forseti-security/policy-library into your own VCS.

This repo contains templates and sample constraints which will form the basis of your policies. So get it into your Git environment and clone it to local for the next step.

Customise sample constraints to fit your needs

As discussed in Concepts, Constraints are defined Templates, which make use of Rego policy language. Nice. So let’s take a sample Constraint, put it in our Policy Library and set the values to what we need. It’s that easy – no need to write new templates or learn Rego if your use case is covered.

In a new branch…

  1. Copy the sample Constraint storage_location.yaml to your Constraints folder.
    $ cp policy-library/samples/storage_location.yaml policy-library/policies/constraints/storage_location.yaml
  2. Replace the sample location (asia-southeast1) in storage_location.yaml with australia-southeast1.
    spec:
    severity: high
    match:
    target: ["organization/*"]
    parameters:
    mode: "allowlist"
    locations:
    - australia-southeast1
    exemptions: []
  3. Push back to your repo – not Forseti’s!
    $ git push https://github.com/<your-repository>/policy-library.git

Policy review

There you go – you’ve customised a sample Constraint. Now you have your own instance of version controlled Policy-as-Code and are ready to apply the power of OPA’s Rego policy language that lies within the parent Template. Impressively easy right?

That’s a pretty simple example. You can browse the rest of Forseti’s Policy Library to view other sample Constraints, Templates and the Rego logic that makes all of this work. These can be adjusted to cover all kinds of use cases across GCP resources.

I suggest working with and editing the sample Constraints before making any changes to Templates.

If you were to write Rego and Templates from scratch, you might even be able to enforce Policy as Code against non-GCP Terraform code.

Terraform Validator

Now, let’s set up the Terraform Validator tool and have it compare a sample piece of Terraform code against the Constraint we configured above. Keep in mind you’ll want to translate what’s done here into steps in your CICD pipeline.

Once the tool is in place, we really just run terraform plan and feed the output into Terraform Validator. The Validator compares it to our Constraints, runs all the abstracted logic we don’t need to worry about and returns 0 or 2 when done for pass / fail respectively. Easy.

So using Terraform if I try to make a bucket in australia-southeast1 it should pass, if I try to make one in the US it should fail. Let’s set up the tool, write some basic Terraform and see how we go.

Setup Terraform Validator

Check for the latest version of terraform-validator from the official terraform-validator GCS bucket.

Very important when using tf version 0.12 or greater. This is the easy way – you can pull from the Terraform Validator Github and make it yourself too.

$ gsutil ls -r gs://terraform-validator/releases

Copy the latest version to the working dir

$ gsutil cp gs://terraform-validator/releases/2020-03-05/terraform-validator-linux-amd64 .

Make it executable

$ chmod 755 terraform-validator-linux-amd64

Ready to go!

Review your Terraform code

We’re going to make a ridiculously simple piece of Terraform that tries to create one bucket in our project to keep things simple.

main.tf

resource "google_storage_bucket" "tf-validator-demo-bucket" {  
  name          = "tf-validator-demo-bucket"
  location      = "US"
  force_destroy = true

  lifecycle_rule {
    condition {
      age = "3"
    }
    action {
      type = "Delete"
    }
  }
}

This is a pretty standard bit of Terraform for a GCS bucket, but made very simple with all the values defined directly in main.tf. Note the location of the bucket – it violates our Constraint that was set to the australia-southeast1 region.

Make the Terraform plan

Warm up Terraform.
Double check your Terraform code if there are any hiccups.

$ terraform init

Make the Terraform plan and store output to file.

$ terraform plan --out=terraform.tfplan

Convert the plan to JSON

$ terraform show -json ./terraform.tfplan > ./terraform.tfplan.json

Validate the non-compliant Terraform plan against your Constraints, for example

$ ./terraform-validator-linux-amd64 validate ./tfplan.tfplan.json --policy-path=../repos/policy-library/

TA-DA!

Found Violations:

Constraint allow_some_storage_location on resource //storage.googleapis.com/tf-validator-demo-bucket: //storage.googleapis.com/tf-validator-demo-bucket is in a disallowed location.

Validate the compliant Terraform plan against your Constraints

Let’s see what happens if we repeat the above, changing the location of our GCS bucket to australia-southeast1.

$ ./terraform-validator-linux-amd64 validate ./tfplan.tfplan.json --policy-path=../repos/policy-library/

Results in..

No violations found.

Success!!!

Now all that’s left to do for your Policy as Code CICD pipeline is to configure the rest of your Constraints and run this check before you go ahead and terraform apply. Be sure to make the apply step dependent on the outcome of the Validator.

Wrap Up

We’ve looked at how to apply Policy as Code to validate our Infrastructure as Code. Sounds pretty modern and DevOpsy doesn’t it.

To recap, we learned about Constraints, which are fully defined instances of Policy as Code. They’re based on YAML Templates that refer to the OPA policy language Rego, but we didn’t have to learn it 🙂

We created our own version controlled Policy Library.

Using the above learning and some handy pre-existing samples, we wrote policies (Constraints) for GCP infrastructure, specifying a whitelist for locations in which GCS buckets could be deployed.

As mentioned there are dozens upon dozens of samples across BigQuery, IAM, networks, MySQL, Google Kubernetes Engine (GKE) and more to work with.

Of course, we stored these configured Constraints in our version-controlled Policy Library.

  • We looked at a simple set of Terraform code to define a GCS bucket, and stored the Terraform plan to a file before applying it.
  • We ran Forseti’s Terraform Validator against the Terraform plan file, and had the Validator compare the plan to our Policy Library.
  • We saw that the results matched our expectations! Compliance with the location specified in our Constraint passed the Validator’s checks, and non-compliance triggered a violation.

Awesome. And the best part is that all this required no special permissions, no infrastructure for servers or agents and no networking.

All of that comes with the full Forseti suite of Inventory taking Config Validation of already deployed resources. We might get to that next time.

References:

https://github.com/GoogleCloudPlatform/terraform-validator https://github.com/forseti-security/policy-library https://www.openpolicyagent.org/docs/latest/policy-language/ https://cloud.google.com/blog/products/identity-security/using-forseti-config-validator-with-terraform-validator https://forsetisecurity.org/docs/latest/concepts/

Creating a Site to Site VPN Connection Between GCP and Azure with Google Private Access

This article demonstrates creating a site to site IPSEC VPN connection between a GCP VPC network and an Azure Virtual Network, enabling private RFC1918 network connectivity between virtual networks in both clouds. This is done using a single PowerShell script leveraging Azure PowerShell and gcloud commands in the Google SDK.

Additionally, we will use Azure Private DNS to enable private access between Azure hosts and GCP APIs (such as Cloud Storage or Big Query).

An overview of the solution is provided here:

Azure to GCP VPN Design

One note before starting – site to site VPN connections between GCP and Azure currently do not support dynamic routing using BGP, however creating some simple routes on either end of the connection will be enough to get going.

Let’s go through this step by step:

Step 1 : Authenticate to Azure

Azure’s account equivalent is a subscription, the following command from Azure Powershell is used to authenticate a user to one or more subscriptions.

Connect-AzAccount

This command will open a browser window prompting you for Microsoft credentials, once authenticated you will be returned to the command line.

Step 2 : Create a Resource Group (Azure)

A resource group is roughly equivalent to a project in GCP. You will need to supply a Location (equivalent to a GCP region):

New-AzResourceGroup `
  -Name "azure-to-gcp" `
  -Location "Australia Southeast"

Step 3 : Create a Virtual Network with Subnets and Routes (Azure)

An Azure Virtual Network is the equivalent of a VPC network in GCP (or AWS), you must define subnets before creating a Virtual Network. In this example we will create two subnets, one Gateway subnet (which needs to be named accordingly) where the VPN gateway will reside, and one subnet named ‘default’ where we will host VMs which will connect to GCP services over the private VPN connection.

Before defining the default subnet we must create and attach a Route Table (equivalent of a Route in GCP), this particular route will be used to route ‘private’ requests to services in GCP (such as Big Query).

# define route table and route to GCP private access
$azroutecfg = New-AzRouteConfig `
  -Name "google-private" `
  -AddressPrefix "199.36.153.4/30" `
  -NextHopType "VirtualNetworkGateway" 

$azrttbl = New-AzRouteTable `
  -ResourceGroupName "azure-to-gcp" `
  -Name "google-private" `
  -Location "Australia Southeast" `
  -Route $azroutecfg

# define gateway subnet
$gatewaySubnet = New-AzVirtualNetworkSubnetConfig  `
  -Name "GatewaySubnet" `
  -AddressPrefix "10.1.2.0/24"

# define default subnet
$defaultSubnet  = New-AzVirtualNetworkSubnetConfig `
  -Name "default" `
  -AddressPrefix "10.1.1.0/24" `
  -RouteTable $azrttbl

# create virtual network and subnets
$vnet = New-AzVirtualNetwork  `
  -Name "azure-to-gcp-vnet" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -AddressPrefix "10.1.0.0/16" `
  -Subnet $gatewaySubnet,$defaultSubnet

Step 4 : Create Network Security Groups (Azure)

Network Security Groups in Azure are stateful firewalls much like Firewall Rules in VPC networks in GCP. Like GCP, the lower priority overrides higher priority rules.

In the example we will create several rules to allow inbound ICMP, TCP and UDP traffic from our Google VPC and RDP traffic from the Internet (which we will use to logon to a VM in Azure to test private connectivity between the two clouds):

# create network security group
$rule1 = New-AzNetworkSecurityRuleConfig `
  -Name rdp-rule `
  -Description "Allow RDP" `
  -Access Allow `
  -Protocol Tcp `
  -Direction Inbound `
  -Priority 100 `
  -SourceAddressPrefix Internet `
  -SourcePortRange * `
  -DestinationAddressPrefix * `
  -DestinationPortRange 3389

$rule2 = New-AzNetworkSecurityRuleConfig `
  -Name icmp-rule `
  -Description "Allow ICMP" `
  -Access Allow `
  -Protocol Icmp `
  -Direction Inbound `
  -Priority 101 `
  -SourceAddressPrefix * `
  -SourcePortRange * `
  -DestinationAddressPrefix * `
  -DestinationPortRange *

$rule3 = New-AzNetworkSecurityRuleConfig `
  -Name gcp-rule `
  -Description "Allow GCP" `
  -Access Allow `
  -Protocol Tcp `
  -Direction Inbound `
  -Priority 102 `
  -SourceAddressPrefix "10.2.0.0/16" `
  -SourcePortRange * `
  -DestinationAddressPrefix * `
  -DestinationPortRange *

$nsg = New-AzNetworkSecurityGroup `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -Name "nsg-vm" `
  -SecurityRules $rule1,$rule2,$rule3

Step 5 : Create Public IP Addresses (Azure)

We need to create two Public IP Address (equivalent of an External IP in GCP) which will be used for our VPN gateway and for the VM we will create:

# create public IP address for VM
$vmpip = New-AzPublicIpAddress `
  -Name "vm-ip" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -AllocationMethod Dynamic

# create public IP address for NW gateway 
$ngwpip = New-AzPublicIpAddress `
  -Name "ngw-ip" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -AllocationMethod Dynamic

Step 6 : Create Virtual Network Gateway (Azure)

The Virtual Network Gateway in Azure is the VPN Gateway equivalent in Azure which will be used to create a VPN tunnel between Azure and a GCP VPN Gateway. This gateway will be placed in the Gateway subnet created previously and one of the Public IP addresses created in the previous step will be assigned to this gateway.

# create virtual network gateway
$ngwipconfig = New-AzVirtualNetworkGatewayIpConfig `
  -Name "ngw-ipconfig" `
  -SubnetId $gatewaySubnet.Id `
  -PublicIpAddressId $ngwpip.Id

# use the AsJob switch as this is a long running process
$job = New-AzVirtualNetworkGateway -Name "vnet-gateway" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -IpConfigurations $ngwipconfig `
  -GatewayType "Vpn" `
  -VpnType "RouteBased" `
  -GatewaySku "VpnGw1" `
  -VpnGatewayGeneration "Generation1" `
  -AsJob

$vnetgw = Get-AzVirtualNetworkGateway `
  -Name "vnet-gateway" `
  -ResourceGroupName "azure-to-gcp"

Step 7 : Create a VPC Network and Subnetwork(s) (GCP)

A VPC network and subnet need to be created in GCP, the subnet defines the VPC address space. This address space must not overlap with the Azure Virtual Network CIDR. For all GCP steps it is assumed that the project is set for client config (e.g. gcloud config set project <>) so it does not need to be specified for each operation. Private Google access should be enabled on all subnets created.

# creating VPC network and subnets
gcloud compute networks create "azure-to-gcp-vpc" `
  --subnet-mode=custom `
  --bgp-routing-mode=regional

gcloud compute networks subnets create "aus-subnet" `
  --network  "azure-to-gcp-vpc" `
  --range "10.2.1.0/24" `
  --region "australia-southeast1" `
  --enable-private-ip-google-access

Step 8 : Create an External IP (GCP)

An external IP address will need to be created in GCP which will be used for the external facing interface of the VPN Gateway.

# create external IP
gcloud compute addresses create "ext-gw-ip" `
  --region "australia-southeast1"

$gcp_ipaddr_obj = gcloud compute addresses describe "ext-gw-ip" `
  --region "australia-southeast1" `
  --format json | ConvertFrom-Json

$gcp_ipaddr = $gcp_ipaddr_obj.address

Step 9 : Create Firewall Rules (GCP)

VPC firewall rules will need to be created in GCP to allow VPN traffic as well as SSH traffic from the internet (which allows you to SSH into VM instances using Cloud Shell).

# create VPN firewall rules
gcloud compute firewall-rules create "vpn-rule1" `
  --network "azure-to-gcp-vpc" `
  --allow tcp,udp,icmp `
  --source-ranges "10.1.0.0/16"

gcloud compute firewall-rules create "ssh-rule1" `
  --network "azure-to-gcp-vpc" `
  --allow tcp:22

Step 10 : Create VPN Gateway and Forwarding Rules (GCP)

Create a VPN Gateway and Forwarding Rules in GCP which will be used to create a tunnel between GCP and Azure.

# create cloud VPN 
gcloud compute target-vpn-gateways create "vpn-gw" `
  --network "azure-to-gcp-vpc" `
  --region "australia-southeast1" `
  --project "azure-to-gcp-project"

# create forwarding rule ESP
gcloud compute forwarding-rules create "fr-gw-name-esp" `
  --ip-protocol ESP `
  --address "ext-gw-ip" `
  --target-vpn-gateway "vpn-gw" `
  --region "australia-southeast1" `
  --project "azure-to-gcp-project"

# creating forwarding rule UDP500
gcloud compute forwarding-rules create "fr-gw-name-udp500" `
  --ip-protocol UDP `
  --ports 500 `
  --address "ext-gw-ip" `
  --target-vpn-gateway "vpn-gw" `
  --region "australia-southeast1" `
  --project "azure-to-gcp-project"

# creating forwarding rule UDP4500
gcloud compute forwarding-rules create "fr-gw-name-udp4500" `
  --ip-protocol UDP `
  --ports 4500 `
  --address "ext-gw-ip" `
  --target-vpn-gateway "vpn-gw" `
  --region "australia-southeast1" `
  --project "azure-to-gcp-project"

Step 10 : Create VPN Tunnel (GCP Side)

Now we will create the GCP side of our VPN tunnel using the Public IP Address of the Azure Virtual Network Gateway created in a previous step. As this example uses a route based VPN the traffic selector values need to be set at 0.0.0.0/0. A PSK (Pre Shared Key) needs to be supplied which will be the same key used when we configure a VPN Connection on the Azure side of the tunnel.

# get peer public IP address of Azure gateway
$azpubip = Get-AzPublicIpAddress `
  -Name "ngw-ip" `
  -ResourceGroupName "azure-to-gcp"

# create VPN tunnel 
gcloud compute vpn-tunnels create "vpn-tunnel-to-azure" `
  --peer-address $azpubip.IpAddress `
  --local-traffic-selector "0.0.0.0/0" `
  --remote-traffic-selector "0.0.0.0/0" `
  --ike-version 2 `
  --shared-secret <<Pre-Shared Key>> `
  --target-vpn-gateway "vpn-gw" `
  --region  "australia-southeast1" `
  --project "azure-to-gcp-project"

Step 11 : Create Static Routes (GCP Side)

As we are using static routing (as opposed to dynamic routing) we will need to define all of the specific routes on the GCP side. We will need to setup routes for both outgoing traffic to the Azure network as well as incoming traffic for the restricted Google API range (199.36.153.4/30).

# create static route (VPN)
gcloud compute routes create "route-to-azure" `
  --destination-range "10.1.0.0/16" `
  --next-hop-vpn-tunnel "vpn-tunnel-to-azure" `
  --network "azure-to-gcp-vpc" `
  --next-hop-vpn-tunnel-region "australia-southeast1" `
  --project "azure-to-gcp-project"

# create static route (Restricted APIs)
gcloud compute routes create apis `
  --network  "azure-to-gcp-vpc" `
  --destination-range "199.36.153.4/30" `
  --next-hop-gateway default-internet-gateway `
  --project "azure-to-gcp-project"

Step 12 : Create a Local Gateway (Azure)

A Local Gateway in Azure is an object that represents the remote gateway (GCP VPN gateway).

# create local gateway
$azlocalgw = New-AzLocalNetworkGateway `
  -Name "local-gateway" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -GatewayIpAddress $gcp_ipaddr `
  -AddressPrefix "10.2.0.0/16"

Step 13 : Create a VPN Connection (Azure)

Now we can setup the Azure side of the VPN Connection which is accomplished by associating the Azure Virtual Network Gateway with the Local Network Gateway. A PSK (Pre Shared Key) needs to be supplied which is the same key used for the GCP VPN Tunnel in step 10.

# create connection
$azvpnconn = New-AzVirtualNetworkGatewayConnection `
  -Name "vpn-connection" `
  -ResourceGroupName "azure-to-gcp" `
  -VirtualNetworkGateway1 $vnetgw `
  -LocalNetworkGateway2 $azlocalgw `
  -Location "Australia Southeast" `
  -ConnectionType IPsec `
  -SharedKey  << Pre-Shared Key >>  `
  -ConnectionProtocol "IKEv2"

VPN Tunnel Established!

At this stage we have created an end to end connection between the virtual networks in both clouds. You should see this reflected in the respective consoles in each provider.

GCP VPN Tunnel to a Azure Virtual Network
Azure VPN Connection to a GCP VPC Network

Congratulations! You have just setup a multi cloud environment using private networking. Now let’s setup Google Private Access for Azure hosts and create VMs on each side to test our setup.

Step 14 : Create a Private DNS Zone for googleapis.com (Azure)

We will now need to create a Private DNS zone in Azure for the googleapis.com domain which will host records to redirect Google API requests to the Restricted API range.

# create private DNS zone
New-AzPrivateDnsZone `
  -ResourceGroupName "azure-to-gcp" `
  -Name "googleapis.com"

# Add A Records   
$Records = @()
$Records += New-AzPrivateDnsRecordConfig `
  -IPv4Address 199.36.153.4
$Records += New-AzPrivateDnsRecordConfig `
  -IPv4Address 199.36.153.5
$Records += New-AzPrivateDnsRecordConfig `
  -IPv4Address 199.36.153.6
$Records += New-AzPrivateDnsRecordConfig `
  -IPv4Address 199.36.153.7

New-AzPrivateDnsRecordSet `
  -Name "restricted" `
  -RecordType A `
  -ResourceGroupName "azure-to-gcp" `
  -TTL 300 `
  -ZoneName "googleapis.com" `
  -PrivateDnsRecords $Records

# Add CNAME Records   
$Records = @()
$Records += New-AzPrivateDnsRecordConfig `
  -Cname "restricted.googleapis.com."

New-AzPrivateDnsRecordSet `
  -Name "*" `
  -RecordType CNAME `
  -ResourceGroupName "azure-to-gcp" `
  -TTL 300 `
  -ZoneName "googleapis.com" `
  -PrivateDnsRecords $Records

# Create VNet Link
New-AzPrivateDnsVirtualNetworkLink `
  -ResourceGroupName "azure-to-gcp" `
  -ZoneName "googleapis.com" `
  -Name "dns-zone-link" `
  -VirtualNetworkId $vnet.Id

Step 15 : Create a Virtual Machine (Azure)

We will create a VM in Azure which we can use to test the VPN tunnel as well as to test Private Google Access over our VPN tunnel.

# create VM
$az_vmlocaladminpwd = ConvertTo-SecureString << Password Param >> `
  -AsPlainText -Force
$Credential = New-Object System.Management.Automation.PSCredential  ("LocalAdminUser", $az_vmlocaladminpwd);

$nic = New-AzNetworkInterface `
  -Name "vm-nic" `
  -ResourceGroupName "azure-to-gcp" `
  -Location "Australia Southeast" `
  -SubnetId $defaultSubnet.Id `
  -NetworkSecurityGroupId $nsg.Id `
  -PublicIpAddressId $vmpip.Id `
  -EnableAcceleratedNetworking `
  -Force

$VirtualMachine = New-AzVMConfig `
  -VMName "windows-desktop" `
  -VMSize "Standard_D4_v3"

$VirtualMachine = Set-AzVMOperatingSystem `
  -VM $VirtualMachine `
  -Windows `
  -ComputerName  "windows-desktop" `
  -Credential $Credential `
  -ProvisionVMAgent `
  -EnableAutoUpdate

$VirtualMachine = Add-AzVMNetworkInterface `
  -VM $VirtualMachine `
  -Id $nic.Id

$VirtualMachine = Set-AzVMSourceImage `
  -VM $VirtualMachine `
  -PublisherName 'MicrosoftWindowsDesktop' `
  -Offer 'Windows-10' `
  -Skus 'rs5-pro' `
  -Version latest

New-AzVM `-ResourceGroupName "azure-to-gcp"
  -Location "Australia Southeast" `
  -VM $VirtualMachine `
  -Verbose

Step 16 : Create a VM Instance (GCP)

We will create a Linux VM in GCP to test connectivity to hosts in Azure using the VPN tunnel we have established.

# create VM instance
gcloud compute instances create "gcp-instance" `
  --zone "australia-southeast1-b" `
  --machine-type "f1-micro" `
  --subnet "aus-subnet" `
  --network-tier PREMIUM `
  --maintenance-policy MIGRATE `
  --image=debian-9-stretch-v20200309 `
  --image-project=debian-cloud `
  --boot-disk-size 10GB `
  --boot-disk-type pd-standard `
  --boot-disk-device-name instance-1 `
  --reservation-affinity any

Test Connectivity

Now we are ready to test connectivity from both sides of the tunnel.

Azure to GCP

Establish a remote desktop (RDP) connection to the Azure VM created in Step 15. Ping the GCP VM instance using its private IP address.

Test Private IP Connectivity from Azure to GCP

GCP to Azure

Now SSH into the GCP Linux VM instance and ping the Azure host using its private IP address.

Test Private IP Connectivity from GCP to Azure

Test Private Google Access from Azure

Now that we have established bi-directional connectivity between the two clouds, we can test private access to Google APIs from our Azure host. Follow the steps below to test private access:

  1. RDP into the Azure VM
  2. Install the Google Cloud SDK ( https://cloud.google.com/sdk/)
  3. Perform an nslookup to ensure that calls to googleapis.com resolve to the restricted API range (e.g. nslookup storage.googleapis.com). You should see a response showing the A records from the googleapis.com Private DNS Zone created in step 14.
  4. Now test connectivity to Google APIs, for example to test access to Google Cloud Storage using gsutil, or test access to Big Query using the bq command

Congratulations! You are now a multi cloud ninja!

Spark in the Google Cloud Platform Part 2

In the previous post in this series Spark in the Google Cloud Platform Part 1, we started to explore the various ways in which we could deploy Apache Spark applications in GCP. The first option we looked at was deploying Spark using Cloud DataProc, a managed Hadoop cluster with various ecosystem components included.

In this post, we will look at another option for deploying Spark in GCP – a Spark Standalone cluster running on GKE.

Spark Standalone refers to the in-built cluster manager provided with each Spark release. Standalone can be a bit of a misnomer as it sounds like a single instance – which it is not, standalone simply refers to the fact that it is not dependent upon any other projects or components – such as Apache YARN, Mesos, etc.

A Spark Standalone cluster consists of a Master node or instance and one of more Worker nodes. The Master node serves as both a master and a cluster manager in the Spark runtime architecture.

The Master process is responsible for marshalling resource requests on behalf of applications and monitoring cluster resources.

The Worker nodes host one or many Executor instances which are responsible for carrying out tasks.

Deploying a Spark Standalone cluster on GKE is reasonably straightforward. In the example provided in this post we will set up a private network (VPC), create a GKE cluster, and deploy a Spark Master pod and two Spark Worker pods (in a real scenario you would typically have many Worker pods).

Once the network and GKE cluster have been deployed, the first step is to create Docker images for both the Master and Workers.

The Dockerfile below can be used to create an image capable or running either the Worker or Master daemons:

Note the shell scripts included in the Dockerfile: spark-master and spark-worker. These will be used later on by K8S deployments to start the relative Master and Worker daemon processes in each of the pods.

Next, we will use Cloud Build to build an image using the Dockerfile are store this in GCR (Google Container Registry), from the Cloud Build directory in our project we will run:

gcloud builds submit --tag gcr.io/spark-demo-266309/spark-standalone

Next, we will create Kubernetes deployments for our Master and Worker pods.

Firstly, we need to get cluster credentials for our GKE cluster named ‘spark-cluster’:

gcloud container clusters get-credentials spark-cluster --zone australia-southeast1-a --project spark-demo-266309

Now from within the k8s-deployments\deploy folder of our project we will use the kubectl command to deploy the Master pod, service and the Worker pods

Starting with the Master deployment, this will deploy our Spark Standalone image into a container running the Master daemon process:

To deploy the Master, run the following:

kubectl create -f spark-master-deployment.yaml

The Master will expose a web UI on port 8080 and an RPC service on port 7077, we will need to deploy a K8S service for this, the YAML required to do this is shown here:

To deploy the Master service, run the following:

kubectl create -f spark-master-service.yaml

Now that we have a Master pod and service up and running, we need to deploy our Workers which are preconfigured to communicate with the Master service.

The YAML required to deploy the two Worker pods is shown here:

To deploy the Worker pods, run the following:

kubectl create -f spark-worker-deployment.yaml

You can now inspect the Spark processes running on your GKE cluster.

kubectl get deployments

Shows…

NAME           READY   UP-TO-DATE   AVAILABLE   AGE
 spark-master   1/1     1            1           7m45s
 spark-worker   2/2     2            2           9s
kubectl get pods

Shows…

NAME                            READY   STATUS    RESTARTS   AGE
 spark-master-f69d7d9bc-7jgmj    1/1     Running   0          8m
 spark-worker-55965f669c-rm59p   1/1     Running   0          24s
 spark-worker-55965f669c-wsb2f   1/1     Running   0          24s

Next, as we need to expose the Web UI for the Master process we will create a LoadBalancer resource. The YAML used to do this is provided here:

To deploy the LB, you would run the following:

kubectl create -f spark-ui-lb.yaml

NOTE This is just an example, for simplicity we are creating an external LoadBalancer with a public IP, this configuration is likely not be appropriate in most real scenarios, alternatives would include an internal LoadBalancer, retraction of Authorized Networks, a jump host, SSH tunnelling or IAP.

Now you’re up and running!

You can access the Master web UI from the Google Console link shown here:

Accessing the Spark Master UI from the Google Cloud Console

The Spark Master UI should look like this:

Spark Master UI

Next we will exec into a Worker pod, get a shell:

kubectl exec -it spark-worker-55965f669c-rm59p -- sh

Now from within the shell environment of a Worker – which includes all of the Spark client libraries, we will submit a simple Spark application:

spark-submit --class org.apache.spark.examples.SparkPi \
 --master spark://10.11.250.98:7077 \
/opt/spark/examples/jars/spark-examples*.jar 10000

You can see the results in the shell, as shown here:

Spark Pi Estimator Example

Additionally, as all of the container logs go to Stackdriver, you can view the application logs there as well:

Container Logs in StackDriver

This is a simple way to get a Spark cluster running, it is not without its downsides and shortcomings however, which include the limited security mechanisms available (SASL, network security, shared secrets).

In the final post in this series we will look at Spark on Kubernetes, using Kubernetes as the Spark cluster manager and interacting with Spark using the Kubernetes API and control plane, see you then.

Full source code for this article is available at: https://github.com/gamma-data/spark-on-gcp

The infrastructure coding for this example uses Powershell and Terraform, and is deployed as follows:

PS > .\run.ps1 private-network apply <<gcp-project>> <<region>>
PS > .\run.ps1 gke apply <<gcp-project>> <<region>> 

Spark in the Google Cloud Platform Part 1

I have been an avid Spark enthusiast since 2014 (the early days..). Spark has featured heavily in every project I have been involved with from data warehousing, ETL, feature extraction, advanced analytics to event processing and IoT applications. I like to think of it as a Swiss army knife for distributed processing.

Curiously enough, the first project I had been involved with for some years that did not feature the Apache Spark project was a green field GCP project which got me thinking… where does Spark fit into the GCP landscape?

Unlike the other major providers who use Spark as the backbone of their managed distributed ETL services with examples such as AWS Glue or the Spark integration runtime option in Azure Data Factory, Google’s managed ETL solution is Cloud DataFlow. Cloud DataFlow which is a managed Apache Beam service does not use a Spark runtime (there is a Spark Runner however this is not an option when using CDF). So where does this leave Spark?

My summation is that although Spark is not a first-class citizen in GCP (as far as managed ETL), it is not a second-class citizen either. This article will discuss the various ways Spark clusters and applications can be deployed within the GCP ecosystem.

Quick Primer on Spark

Every Spark application contains several components regardless of deployment mode, the components in the Spark runtime architecture are:

  • the Driver
  • the Master
  • the Cluster Manager
  • the Executor(s), which run on worker nodes or Workers

Each component has a specific role in executing a Spark program and all of the Spark components run in Java virtual machines (JVMs).

Spark Runtime Architecture

Cluster Managers schedule and manage distributed resources (compute and memory) across the nodes of the cluster. Cluster Managers available for Spark include:

  • Standalone
  • YARN (Hadoop)
  • Mesos
  • Kubernetes

Spark on DataProc

This is perhaps the simplest and most integrated approach to using Spark in the GCP ecosystem.

DataProc is GCP’s managed Hadoop Service (akin to AWS EMR or HDInsight on Azure). DataProc uses Hadoop/YARN as the Cluster Manager. DataProc clusters can be deployed on a private network (VPC using RFC1918 address space), supports encryption at Rest using Google Managed or Customer Managed Keys in KMS, supports autoscaling and the use of Preemptible Workers, and can be deployed in a HA config.

Furthermore, DataProc clusters can enforce strong authentication using Kerberos which can be integrated into other directory services such as Active Directory through the use of cross realm trusts.

Deployment

DataProc clusters can be deployed using the gcloud dataproc clusters create command or using IaC solutions such as Terraform. For this article I have included an example in the source code using the gcloud command to deploy a DataProc cluster on a private network which was created using Terraform.

Integration

The beauty of DataProc is its native integration into IAM and the GCP service plane. Having been a long-time user of AWS EMR, I have found that the usability and integration are in many ways superior in GCP DataProc. Let’s look at some examples…

IAM and IAP (TCP Forwarding)

DataProc is integrated into Cloud IAM using various coarse grained permissions use as dataproc.clusters.use and simplified IAM Roles such as dataproc.editor or dataproc.admin. Members with bindings to the these roles can perform tasks such as submitting jobs and creating workflow templates (which we will discuss shortly), as well as accessing instances such as the master node instance or instances in the cluster using IAP (TCP Forwarding) without requiring a public IP address or a bastion host.

DataProc Jobs and Workflows

Spark jobs can be submitted using the console or via gcloud dataproc jobs submit as shown here:

Submitting a Spark Job using gcloud dataproc jobs submit

Cluster logs are natively available in StackDriver and standard out from the Spark Driver is visible from the console as well as via gcloud commands.

Complex Workflows can be created by adding Jobs as Steps in Workflow Templates using the following command:

gcloud dataproc workflow-templates add-job spark

Optional Components and the Component Gateway

DataProc provides you with a Hadoop cluster including YARN and HDFS, a Spark runtine – which includes Spark SQL and SparkR. DataProc also supports several optional components including Anaconda, Jupyter, Zeppelin, Druid, Presto, and more.

Web interfaces to some of these components as well as the management interfaces such as the Resource Manager UI or the Spark History Server UI can be accessed through the Component Gateway.

This is a Cloud IAM integrated gateway (much like IAP) which can allow access through an authenticated and authorized console session to web UIs in the cluster – without the need for SSH tunnels, additional firewall rules, bastion hosts, or public IPs. Very cool.

Links to the component UIs as well as built in UIs like the YARN Resource Manager UI are available directly from through the console.

Jupyter

Jupyter is a popular notebook application in the data science and analytics communities used for reproducible research. DataProc’s Jupyter component provides a ready-made Spark application vector using PySpark. If you have also installed the Anaconda component you will have access to the full complement of scientific and mathematic Python packages such as Pandas and NumPy which can be used in Jupyter notebooks as well. Using the Component Gateway, Jupyer notebooks can be accessed directly from the Google console as shown here:

Jupyter Notebooks using DataProc

From this example you can see that I accessed source data from a GCS bucket and used HDFS as local scratch space.

Furthermore, notebooks are automagically saved in your integrated Cloud Storage DataProc staging bucket and can be shared amongst analysts or accessed at a later time. These notebooks also persist beyond the lifespan of the cluster.

Next up we will look at deploying a Spark Standalone cluster on a GKE cluster, see you then!

Query Cloud SQL through Big Query

This article demonstrates Cloud SQL federated queries for Big Query, a neat and simple to use feature.

Connecting to Cloud SQL

One of the challenges presented when using Cloud SQL on a private network (VPC) is providing access to users. There are several ways to accomplish this which include:

  • open the database port on the VPC Firewall (5432 for example for Postgres) and let users access the database using a command line or locally installed GUI tool (may not be allowed in your environment)
  • provide a web based interface deployed on your VPC such as PGAdmin deployed on a GCE instance or GKE pod (adds security and management overhead)
  • use the Cloud SQL proxy (requires additional software to be installed and configured)

In additional, all of the above solutions require direct IP connectivity to the instance which may not always be available. Furthermore each of these operations requires the user to present some form of authentication – in many cases the database user and password which then must be managed at an individual level.

Enter Cloud SQL federated queries for Big Query…

Big Query Federated Queries for Cloud SQL

Big Query allows you to query tables and views in Cloud SQL (currently MySQL and Postgres) using the Federated Queries feature. The queries could be authorized views in Big Query datasets for example.

This has the following advantages:

  • Allows users to authenticate and use the GCP console to query Cloud SQL
  • Does not require direct IP connectivity to the user or additional routes or firewall rules
  • Leverages Cloud IAM as the authorization mechanism – rather that unmanaged db user accounts and object level permissions
  • External queries can be executed against a read replica of the Cloud SQL instance to offload query IO from the master instance

Setting it up

Setting up big query federated queries for Cloud SQL is exceptionally straightforward, a summary of the steps are provided below:

Step 1. Enable a Public IP on the Cloud SQL instance

This sounds bad, but it isn’t really that bad. You need to enable a public interface for Big Query to be able to establish a connection to Cloud SQL, however this is not accessed through the actual public internet – rather it is accessed through the Google network using the back end of the front end if you will.

Furthermore, you configure an empty list of authorized networks which effectively shields the instance from the public network, this can be configured in Terraform as shown here:

This configuration change can be made to a running instance as well as during the initial provisioning of the instance.

As shown below you will get a warning dialog in the console saying that you have no authorized networks – this is by design.

Cloud SQL Public IP Enabled with No Authorized Networks

Step 2. Create a Big Query dataset which will be used to execute the queries to Cloud SQL

Connections to Cloud SQL are defined in a Big Query dataset, this can also be use to control access to Cloud SQL using authorized views controlled by IAM roles.

Step 3. Create a connection to Cloud SQL

To create a connection to Cloud SQL from Big Query you must first enable the BigQuery Connection API, this is done at a project level.

As this is a fairly recent feature there isn’t great coverage with either the bq tool or any of the Big Query client libraries to do this so we will need to use the console for now…

Under the Resources -> Add Data link in the left hand panel of the Big Query console UI, select Create Connection. You will see a side info panel with a form to enter connection details for your Cloud SQL instance.

In this example I will setup a connection to a Cloud SQL read replica instance I have created:

Creating a Big Query Connection to Cloud SQL

More information on the Big Query Connections API can be found at: https://cloud.google.com/bigquery/docs/reference/bigqueryconnection/rest

The following permissions are associated with connections in Big Query:

bigquery.connections.create
bigquery.connections.get
bigquery.connections.list
bigquery.connections.use
bigquery.connections.update
bigquery.connections.delete

These permissions are conveniently combined into the following predefined roles:

roles/bigquery.connectionAdmin    (BigQuery Connection Admin)         
roles/bigquery.connectionUser     (BigQuery Connection User)          

Step 4. Query away!

Now the connection to Cloud SQL can be accessed using the EXTERNAL_QUERY function in Big Query, as shown here:

Querying Cloud SQL from Big Query

Google Cloud SQL – Availability for PostgreSQL – Part II (Read Replicas)

In this post we will look at read replicas as an additional method to achieve multi zone availability for Cloud SQL, which gives us – in turn – the ability to offload (potentially expensive) IO operations such as user created backups or read operations without adding load to the master instance.

In the previous post in this series we looked at Regional availability for PostgreSQL HA using Cloud SQL:

Recall that this option was simple to implement and worked relatively seamlessly and transparently with respect to zonal failover.

Now let’s look at read replicas in Cloud SQL as an additional measure for availability.

Deploying Read Replica(s)

Deploying read replicas is slightly more involved than simple regional (high) availability, as you will need to define each replica or replicas as a separate Cloud SQL instance which is a slave to the primary instance (the master instance).

An example using Terraform is provided here, starting by creating the master instance:

Next you would specify one or more read replicas (typically in a zone other than the zone the master is in):

Note that several of the options supplied are omitted when creating a read replica database instance, such as the backup and maintenance options – as these operations cannot be performed on a read replica as we will see later.

Cloud SQL Instances – showing master and replica
Cloud SQL Master Instance

Voila! You have just set up a master instance (the primary instance your application and/or users will connect to) along with a read replica in a different zone which will be asynchronously updated as changes occur on the master instance.

Read Replicas in Action

Now that we have created a read replica, lets see it in action. After connecting to the read replica (like you would any other instance), attempt to access a table that has not been created on the master as shown here:

SELECT operation from the replica instance

Now create the table and insert some data on the master instance:

Create a table and insert a record on the master instance

Now try the select operation on the replica instance:

SELECT operation from the replica instance (after changes have been made on the master)

It works!

Some Points to Note about Cloud SQL Read Replicas

  • Users connect to a read replica as a normal database connection (as shown above)
  • Google managed backups (using the console or gcloud sql backups create .. ) can NOT be performed against replica instances
  • Read replicas can be used to offload IO intensive operations from the the master instance – such as user managed backup operations (e.g. pg_dump)
pg_dump operation against a replica instance
  • BE CAREFUL Despite their name, read replicas are NOT read only, updates can be made which will NOT propagate back to the master instance – you could get yourself in an awful mess if you allow users to perform INSERT, UPDATE, DELETE, CREATE or DROP operations against replica instances.

Promoting a Read Replica

If required a read replica can be promoted to a standalone Cloud SQL instance, which is another DR option. Keep in mind however as the read replica is updated in an asynchronous manner, promotion of a read replica may result in a loss of data (hopefully not much but a loss nonetheless). Your application RPO will dictate if this is acceptable or not.

Promotion of a read replica is reasonably straightforward as demonstrated here using the console:

Promoting a read replica using the console

You can also use the following gcloud command:

 gcloud sql instances promote-replica  <replica_instance_name>

Once you click on the Promote Replica button you will see the following warning:

Promoting a read replica using the console

This simply states that once you promote the replica instance your instance will become an independent instance with no further relationship with the master instance. Once accepted and the promotion process is complete, you can see that you now have two independent Cloud SQL instances (as advertised!):

Promoted Cloud SQL instance

Some of the options you would normally configure with a master instance would need to be configured on the promoted replica instance – such as high availability, maintenance and scheduled backups – but in the event of a zonal failure you would be back up and running with virtually no data loss!

Full source code for this article is available at: https://github.com/gamma-data/cloud-sql-postgres-availability-tutorial

Google Cloud SQL – Availability, Replication, Failover for PostgreSQL – Part I

In this multi part blog we will explore the features available in Google Cloud SQL for High Availability, Backup and Recovery, Replication and Failover and Security (at rest and in transit) for the PostgreSQL DBMS engine. Some of these features are relatively hot of the press and in Beta – which still makes them available for general use.

We will start by looking at the High Availability (HA) options available to you when using the PostgreSQL engine in Google Cloud SQL.

Most of you would be familiar with the concepts of High Availability, Redundancy, Fault Tolerance, etc but let’s start with a definition of HA anyway:

High availability (HA) is a characteristic of a system, which aims to ensure an agreed level of operational performance, usually uptime, for a higher than normal period.

Wikipedia

Higher than a normal period is quite subjective, typically this is quantified by a percentage represented by a number of “9s”, that is 99.99% (which would be quoted as “four nines”), this would allot you 52.60 minutes of downtime over a one-year period.

Essentially the number of 9’s required will drive your bias towards the options available to you for Cloud SQL HA.

We will start with Cloud SQL HA in its simplest form, Regional Availability.

Regional Availability

Knowing what we know about the Google Cloud Platform, regional availability means that our application or service (in this case Cloud SQL) should be resilient to a failure of any one zone in our region. In fact, as all GCP regions have at least 3 zones – two zones could fail, and our application would still be available.

Regional availability for Cloud SQL (which Google refers to as High Availability), creates a standby instance in addition to the primary instance and uses a regional Persistent Disk resource to store the database instance data, transaction log and other state files, which is synchronously replicated to a Persistent Disk resource local to the zones that the primary and standby instances are located in.

A shared IP address (like a Virtual IP) is used to serve traffic to the healthy (normally primary) Cloud SQL instance.

An overview of Cloud SQL HA is shown here:

Cloud SQL High Availability

Implementing High Availability for Cloud SQL

Implementing Regional Availability for Cloud SQL is dead simple, it is one argument:

availability_type = "REGIONAL"

Using the gcloud command line utility, this would be:

gcloud sql instances create postgresql-instance-1234 \
  --availability-type=REGIONAL \
  --database-version= POSTGRES_9_6

Using Terraform (with a complete set of options) it would look like:

resource "google_sql_database_instance" "postgres_ha" {
  provider = google-beta
  region = var.region
  project = var.project
  name = "postgresql-instance-${random_id.instance_suffix.hex}"
  database_version = "POSTGRES_9_6"
  settings {
   tier = var.tier
   disk_size = var.disk_size
   activation_policy = "ALWAYS"
   disk_autoresize = true
   disk_type = "PD_SSD"
   availability_type = "REGIONAL"
   backup_configuration {
     enabled = true
     start_time = "00:00"
   }
   ip_configuration  {
     ipv4_enabled = false
     private_network = google_compute_network.private_network.self_link
   }
   maintenance_window  {
     day = 7
     hour = 0
     update_track = "stable"
   }
  }
 } 

Once deployed you will notice a few different items in the console, first from the instance overview page you can see that the High Availability option is ENABLED for your instance.

Second, you will see a Failover button enabled on the detailed management view for this instance.

Failover

Failovers and failbacks can be initiated manually or automatically (should the primary be unresponsive). A manual failover can be invoked by executing the command:

gcloud sql instances failover postgresql-instance-1234

There is an --async option which will return immediately, invoking the failover operation asynchronously.

Failover can also be invoked from the Cloud Console using the Failover button shown previously. As an example I have created a connection to a regionally available Cloud SQL instance and started a command which runs a loop and prints out a counter:

Now using the gcloud command shown earlier, I have invoked a manual failover of the Cloud SQL instance.

Once the failover is initiated, the client connection is dropped (as the server is momentarily unavailable):

The connection can be immediately re-established afterwards, the state of the running query is lost – importantly no data is lost however. If your application clients had retry logic in their code and they weren’t executing a long running query, chances are no one would notice! Once reconnecting normal database activities can be resumed:

A quick check of the instance logs will show that the failover event has occured:

Now when you return to the instance page in the console you will see a Failback button, which indicates that your instance is being served by the standby:

Note that there may be a slight delay in the availability of this option as the replica is still being synched.

It is worth noting that nothing comes for free! When you run in REGIONAL or High Availability mode – you are effectively paying double the costs as compared to running in ZONAL mode. However availability and cost have always been trade-offs against one another – you get what you pay for…

More information can be found at: https://cloud.google.com/sql/docs/postgres/high-availability

Next up we will look at read replicas (and their ability to be promoted) as another high availability alternative in Cloud SQL.

Google Cloud Storage Object Notifications using Slack

This article describes the steps to integrate Slack with Google Cloud Functions to get notified about object events within a specified Google Cloud Storage bucket.

Google Cloud Storage Object Notifications using Slack

Events could include the creation of new objects, as well as delete, archive or metadata operations performed on a given bucket.

This pattern could be easily extended to other event sources supported by Cloud Functions including:

  • Cloud Pub/Sub messages
  • Cloud Firestore and Firebase events
  • Stackdriver log entries

More information can be found at https://cloud.google.com/functions/docs/concepts/events-triggers.

The prerequisite steps to configure Slack are provided here:

1. First you will need to create a Slack app (assuming you have already set up an account and a workspace). The following screenshots demonstrate this process:

Create a Slack app
Give the app a name and associate it with an existing Slack workspace

2. Next you need to Enable and Activate Incoming Webhooks to your app and add this to your workspace. The following screenshots demonstrate this process:

Enable Incoming Web Hooks for the app
Activate incoming webhooks
Add the webhook to your workspace

3. Next you need to specify a channel for notifications generated from object events.

Select a channel for the webhook

4. Now you need to copy the Webhook url provided, you will use this later in your Cloud Function.

Copy the webhook URL to the clipboard

Treat your webhook url as a secret, do not upload this to a public source code repository

Next you need to create your Cloud Function, this example uses Python but you can use an alternative runtime including Node.js or Go.

This example templates the source code using the Terraform template_file data source. The function source code is shown here:

Within your Terraform code you need to render your Cloud Function code substituting the slack_webhook_url for it’s value which you will supply as a Terraform variable. The rendered template file is then placed in a local directory along with a requirements.txt file and zipped up. The resulting Zip archive is uploaded to a specified bucket where it will be sourced to create the Cloud Function.

Now you need to create the Cloud Function, the following HCL snippet demonstrates this:

The event_trigger block in particular specifies which GCS bucket to watch and what events will trigger invocation of the function. Bucket events include:

  • google.storage.object.finalize (the creation of a new object)
  • google.storage.object.delete
  • google.storage.object.archive
  • google.storage.object.metadataUpdate

You could add additional logic to the Cloud Function code to look for specific object names or naming patterns, but keep in mind the function will fire upon every event matching the event_type and resource criteria.

To deploy the function, you would simply run:

terraform apply -var="slack_webhook_url=https://hooks.slack.com/services/XXXXXXXXX/XXXXXXXXX/XXXXXXXXXXXXXXXXXXXXXXXX"

Now once you upload a file named test-object.txt, voilà!:

Slack notification for a new object created

Full source code is available at: https://github.com/gamma-data/gcs-object-notifications-using-slack