Azure DevOps with OpenShift
This article will teach you how to integrate Azure DevOps with the OpenShift cluster to build and deploy your app there. You will learn how to run Azure Pipelines self-hosted agents on OpenShift and use the oc client from your pipelines. If you are interested in Azure DevOps you can read my previous article about that platform and Terraform used together to prepare the environment and run the Spring Boot app on the Azure cloud.
Before we begin, let me clarify some things and explain my decisions. If you were searching for something about Azure DevOps and OpenShift integration, you came across several articles about the Red Hat Azure DevOps extension for OpenShift. I won’t use that extension. In my opinion, it is not actively developed right now, and therefore it provides some limitations that may complicate our integration process. On the other hand, it won’t offer many useful features, so we can do just as well without it.
You will also find articles that show how to prepare a self-hosted agent image based on the Red Hat dotnet-runtime as a base image (e.g. this one). I also won’t use it. Instead, I’m going to leverage the image built on top of UBI9 provided by the tool called Blue Agent (formerly Azure Pipelines Agent). It is a self-hosted Azure Pipelines agent for Kubernetes, easy to run, secure, and auto-scaled. We will have to modify that image slightly, but more details later.
Prerequisites
In order to proceed with the exercise, we need an active subscription to the Azure cloud and an instance of Azure DevOps. We also have to run the OpenShift cluster, which is accessible for our pipelines running on Azure DevOps. I’m running that cluster also on the Azure cloud using the Azure Red Hat OpenShift managed service (ARO). The details about Azure DevOps creation or OpenShift installation are out of the scope of that article.
Source Code
If you would like to try this exercise by yourself, you may always take a look at my source code. Today you will have to clone two sample Git repositories. The first one contains a sample Spring Boot app used in our exercise. We will try to build that app with Azure Pipelines and deploy it on OpenShift. The second repository is a fork of the official Blue Agent repository. It contains a new version of the Dockerfile for our sample self-agent image based on Red Hat UBI9. Once you clone both of these repositories, you just need to follow my instructions.
Azure DevOps Self-Hosted Agent on OpenShift with Blue Agent
Build the Agent Image
In this section, we will build the image of the self-agent based on UBI9. Then, we will run it on the OpenShift cluster. We need to open the Dockerfile in the repository located in the src/docker/Dockerfile-ubi9 path. We don’t need to change much inside that file. It contains several clients, e.g. for AWS or Azure interaction. We will include the line for installing the oc client, which allows us to interact with OpenShift.
RUN curl -s https://mirror.openshift.com/pub/openshift-v4/x86_64/clients/ocp/stable/openshift-client-linux.tar.gz -o - | tar zxvf - -C /usr/bin/
After that, we need to build a new image. You can completely omit this step and pull the final image published on my Docker account and available under the piomin/blue-agent:ubi9 tag.
$ docker build -t piomin/blue-agent:ubi9 -f Dockerfile-ubi9 \
--build-arg JQ_VERSION=1.6 \
--build-arg AZURE_CLI_VERSION=2.63.0 \
--build-arg AWS_CLI_VERSION=2.17.42 \
--build-arg GCLOUD_CLI_VERSION=490.0.0 \
--build-arg POWERSHELL_VERSION=7.2.23 \
--build-arg TINI_VERSION=0.19.0 \
--build-arg BUILDKIT_VERSION=0.15.2 \
--build-arg AZP_AGENT_VERSION=3.243.1 \
--build-arg ROOTLESSKIT_VERSION=2.3.1 \
--build-arg GO_VERSION=1.22.7 \
--build-arg YQ_VERSION=4.44.3 .We can use a Helm chart to install Blue Agent on Kubernetes. This project is still under active development. I could not customize it with parameters to prepare a chart for installing Blue Agent on OpenShift. So, I just set some of them inside the values.yaml file:
pipelines:
organizationURL: https://dev.azure.com/pminkows
personalAccessToken: <AZURE_DEVOPS_PERSONAL_ACCESS_TOKEN>
poolName: Default
image:
repository: piomin/blue-agent
version: 2
flavor: ubi9Deploy Agent on OpenShift
We can generate the YAML manifests for the defined parameters without installing it with the following command:
$ helm template -f blue-agent-values.yaml --dry-run .In order to run it on OpenShift, we need to customize the Deployment object. First of all, I had to grant the privileged SCC (Security Context Constraint) to the container and remove some fields from the securityContext section. Here’s our Deployment object. It refers to the objects previously generated by the Helm chart: agent-blue-agent ServiceAccount and the Secret with the same name.
kind: Deployment
apiVersion: apps/v1
metadata:
name: agent-blue-agent
labels:
app.kubernetes.io/component: agent
app.kubernetes.io/instance: agent
app.kubernetes.io/managed-by: Helm
app.kubernetes.io/name: blue-agent
app.kubernetes.io/part-of: blue-agent
app.kubernetes.io/version: 3.243.1
helm.sh/chart: blue-agent-7.0.3
spec:
replicas: 3
selector:
matchLabels:
app.kubernetes.io/instance: agent
app.kubernetes.io/name: blue-agent
template:
metadata:
labels:
app.kubernetes.io/instance: agent
app.kubernetes.io/name: blue-agent
annotations:
cluster-autoscaler.kubernetes.io/safe-to-evict: 'false'
spec:
nodeSelector:
kubernetes.io/os: linux
restartPolicy: Always
serviceAccountName: agent-blue-agent
schedulerName: default-scheduler
terminationGracePeriodSeconds: 3600
securityContext: {}
containers:
- resources:
limits:
cpu: '2'
ephemeral-storage: 8Gi
memory: 4Gi
requests:
cpu: '1'
ephemeral-storage: 2Gi
memory: 2Gi
terminationMessagePath: /dev/termination-log
lifecycle:
preStop:
exec:
command:
- bash
- '-c'
- ''
- 'rm -rf ${AZP_WORK};'
- 'rm -rf ${TMPDIR};'
name: azp-agent
env:
- name: AGENT_DIAGLOGPATH
value: /app-root/azp-logs
- name: VSO_AGENT_IGNORE
value: AZP_TOKEN
- name: AGENT_ALLOW_RUNASROOT
value: '1'
- name: AZP_AGENT_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.name
- name: AZP_URL
valueFrom:
secretKeyRef:
name: agent-blue-agent
key: organizationURL
- name: AZP_POOL
value: Default
- name: AZP_TOKEN
valueFrom:
secretKeyRef:
name: agent-blue-agent
key: personalAccessToken
- name: flavor_ubi9
- name: version_7.0.3
securityContext:
privileged: true
imagePullPolicy: Always
volumeMounts:
- name: azp-logs
mountPath: /app-root/azp-logs
- name: azp-work
mountPath: /app-root/azp-work
- name: local-tmp
mountPath: /app-root/.local/tmp
terminationMessagePolicy: File
image: 'piomin/blue-agent:ubi9'
serviceAccount: agent-blue-agent
volumes:
- name: azp-logs
emptyDir:
sizeLimit: 1Gi
- name: azp-work
ephemeral:
volumeClaimTemplate:
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 10Gi
storageClassName: managed-csi
volumeMode: Filesystem
- name: local-tmp
ephemeral:
volumeClaimTemplate:
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: managed-csi
volumeMode: Filesystem
dnsPolicy: ClusterFirst
strategy:
type: RollingUpdate
rollingUpdate:
maxUnavailable: 25%
maxSurge: 50%
revisionHistoryLimit: 10
progressDeadlineSeconds: 600
After removing the --dry-run option from the helm template command we can install the solution on OpenShift. It’s worth noting that there were some problems with the Deployment object in the Helm chart, so we will apply it directly later.
Before applying Deployment we have to add privileged SCC to the ServiceAccount used by the agent. By the way, adding privileged SCC is not the best approach to managing containers on OpenShift. However, the oc client installed in the image creates a directory during the login procedure
$ oc adm policy add-scc-to-user privileged -z agent-blue-agentOnce we deploy an agent on OpenShift we should see three running pods. They are trying to connect to the Default pool defined in the Azure DevOps for our self-hosted agent.
$ oc get po
NAME READY STATUS RESTARTS AGE
agent-blue-agent-5458b9b76d-2gk2z 1/1 Running 0 13h
agent-blue-agent-5458b9b76d-nwcxh 1/1 Running 0 13h
agent-blue-agent-5458b9b76d-tcpnp 1/1 Running 0 13hConnect Self-hosted Agent to Azure DevOps
Let’s switch to the Azure DevOps instance. Then, we should go to our project. After that, we need to go to the Organization Settings -> Agent pools. We need to create a new agent pool. The pool name depends on the name configured for the Blue Agent deployed on OpenShift. In our case, this name is Default.
Once we create a pool we should see all three instances of agents in the following list.
We can switch to the OpenShift once again. Then, let’s take a look at the logs printed out by one of the agents. As you see, it has been started successfully and listens for the incoming jobs.
If agents are running on OpenShift and they successfully connect with Azure DevOps, we finished the first part of our exercise. Now, we can create a pipeline for our sample Spring Boot app.
Create Azure DevOps Pipeline for OpenShift
Azure Pipeline Definition
Firstly, we need to go to the sample-spring-boot-web repository. The pipeline is configured in the azure-pipelines.yml file in the repository root directory. Let’s take a look at it. It’s very simple simple. I’m just using the Azure DevOps Command-Line task to interact with OpenShift through the oc client. Of course, it has to define the target agent pool used for running its jobs (1). In the first step, we need to log in to the OpenShift cluster (2). We can use the internal address of the Kubernetes Service, since the agent is running inside the cluster. All the actions should be performed inside our sample myapp project (3). We need to create BuildConfig and Deployment objects using the templates from the repository (4). The pipeline uses its BuildId parameter to the output image. Finally, it starts the build configured by the previously applied BuildConfig object (5).
trigger:
- master
# (1)
pool:
name: Default
steps:
# (2)
- task: CmdLine@2
inputs:
script: 'oc login https://172.30.0.1:443 -u kubeadmin -p $(OCP_PASSWORD) --insecure-skip-tls-verify=true'
displayName: Login to OpenShift
# (3)
- task: CmdLine@2
inputs:
script: 'oc project myapp'
displayName: Switch to project
# (4)
- task: CmdLine@2
inputs:
script: 'oc process -f ocp/openshift.yaml -o yaml -p IMAGE_TAG=v1.0-$(Build.BuildId) -p NAMESPACE=myapp | oc apply -f -'
displayName: Create build
# (5)
- task: CmdLine@2
inputs:
script: 'oc start-build sample-spring-boot-web-bc -w'
failOnStderr: true
displayName: Start build
timeoutInMinutes: 5
- task: CmdLine@2
inputs:
script: 'oc status'
displayName: Check statusIntegrate Azure Pipelines with OpenShift
We use the OpenShift Template object for defining the YAML manifest with Deployment and BuildConfig. The BuildConfig object typically manages the image build process on OpenShift. In order to build the image directly from the source code, it uses the source-2-image (S2I) tool. We need to set at least three parameters to configure the process properly. The first of them is the address of the output image (1). We can use the internal OpenShift repository available at image-registry.openshift-image-registry.svc:5000 or any other external registry like Quay or Docker Hub. We should also set the name of the builder image (2). Our app requires at least Java 21. Of course, the process requires the source code repository as the input (3). At the same time, we define the Deployment object. It uses the image previously built by the BuildConfig object (4). The whole template takes two input parameters: IMAGE_TAG and NAMESPACE (5).
ind: Template
apiVersion: template.openshift.io/v1
metadata:
name: sample-spring-boot-web-tmpl
objects:
- kind: BuildConfig
apiVersion: build.openshift.io/v1
metadata:
name: sample-spring-boot-web-bc
labels:
build: sample-spring-boot-web-bc
spec:
# (1)
output:
to:
kind: DockerImage
name: 'image-registry.openshift-image-registry.svc:5000/${NAMESPACE}/sample-spring-boot-web:${IMAGE_TAG}'
# (2)
strategy:
type: Source
sourceStrategy:
from:
kind: ImageStreamTag
namespace: openshift
name: 'openjdk-21:stable'
# (3)
source:
type: Git
git:
uri: 'https://github.com/piomin/sample-spring-boot-web.git'
- kind: Deployment
apiVersion: apps/v1
metadata:
name: sample-spring-boot-web
labels:
app: sample-spring-boot-web
app.kubernetes.io/component: sample-spring-boot-web
app.kubernetes.io/instance: sample-spring-boot-web
spec:
replicas: 1
selector:
matchLabels:
deployment: sample-spring-boot-web
template:
metadata:
labels:
deployment: sample-spring-boot-web
spec:
containers:
- name: sample-spring-boot-web
# (4)
image: 'image-registry.openshift-image-registry.svc:5000/${NAMESPACE}/sample-spring-boot-web:${IMAGE_TAG}'
ports:
- containerPort: 8080
protocol: TCP
- containerPort: 8443
protocol: TCP
# (5)
parameters:
- name: IMAGE_TAG
displayName: Image tag
description: The output image tag
value: v1.0
required: true
- name: NAMESPACE
displayName: Namespace
description: The OpenShift Namespace where the ImageStream resides
value: openshiftCurrently, OpenShift doesn’t provide OpenJDK 21 image by default. So we need to manually import it to our cluster before running the pipeline.
$ oc import-image openjdk-21:stable \
--from=registry.access.redhat.com/ubi9/openjdk-21:1.20-2.1725851045 \
--confirmNow, we can create a pipeline in Azure DevOps. In order to do it, we need to go to the Pipelines section, and then click the New pipeline button. After that, we just need to pass the address of our repository with the pipeline definition.
Our pipeline requires the OCP_PASSWORD input parameter with the OpenShift admin user password. We can set it as the pipeline secret variable. In order to do that, we need to edit the pipeline and then click the Variables button.
Run the Pipeline
Finally, we can run our pipeline. If everything finishes successfully, the status of the job is Success. It takes around one minute to execute all the steps defined in the pipeline.
We can see detailed logs for each step.
Each time, we run a pipeline a new build on OpenShift starts. Note, that the pipeline updates the BuildConfig object with the new version of the output image.
We can take a look at detailed logs of each build. Within such a build OpenShift starts a new pod, which performs the whole process. It uses the S2I approach for building the image from the source code and pushing that image to the internal OpenShift registry.
Finally, let’s take a look at the Deployment. As you see, it was reloaded with the latest version of the image and worked fine.
$ oc describe deploy sample-spring-boot-web -n myapp
Name: sample-spring-boot-web
Namespace: myapp
CreationTimestamp: Wed, 11 Sep 2024 16:09:11 +0200
Labels: app=sample-spring-boot-web
app.kubernetes.io/component=sample-spring-boot-web
app.kubernetes.io/instance=sample-spring-boot-web
Annotations: deployment.kubernetes.io/revision: 3
Selector: deployment=sample-spring-boot-web
Replicas: 1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: deployment=sample-spring-boot-web
Containers:
sample-spring-boot-web:
Image: image-registry.openshift-image-registry.svc:5000/myapp/sample-spring-boot-web:v1.0-134
Ports: 8080/TCP, 8443/TCP
Host Ports: 0/TCP, 0/TCP
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: sample-spring-boot-web-78559697c9 (0/0 replicas created), sample-spring-boot-web-7985d6b844 (0/0 replicas created)
NewReplicaSet: sample-spring-boot-web-5584447f5d (1/1 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 19m deployment-controller Scaled up replica set sample-spring-boot-web-5584447f5d to 1
Normal ScalingReplicaSet 17m deployment-controller Scaled down replica set sample-spring-boot-web-7985d6b844 to 0 from 1By the way, Azure Pipelines jobs are “load-balanced” between the agents. Here’s the name of the agent used for the first pipeline run.
Here’s the name of the agent used for the second pipeline run.
There are three instances of the agent running on OpenShift. So, Azure DevOps can process max 3 pipeline runs. By the way, we could enable autoscaling for Blue Agent based on KEDA.
Final Thoughts
In this article, I showed the simplest and most OpenShift-native approach to building CI/CD pipelines on Azure DevOps. We just need to use the oc client on the agent image and the OpenShift BuildConfig object to orchestrate the whole process of building and deploying the Spring Boot app on the cluster. Of course, we could implement the same process in several different. For example, we could leverage the plugins for Kubernetes and completely omit the tools provided by OpenShift. On the other hand, it is possible to use Argo CD for the delivery phase, and Azure Pipelines for the integration phase.
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