GitOps for Kubernetes using Github Actions
© Atul R
Github Actions
Allows you to create automated workflows for building, testing, and deploying your code right from GitHub.
on:
push:
branches:
- master
jobs:
deploy-my-app:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- run: echo "step 1"
- run: echo "step 2"
- run: echo "step 3"
.github/workflows/mytask.yaml
Kubernetes
Container orchestration platform:
K8s is a system to manage, scale and deploy applications packaged as containers.
Desired state config
--------------------
...
...
image: eu.gcr.io/app:af7d5b9e
cpu: 400m
memory: 300Mi
replica : 3
...
...
host: myapp.example.com
...
...# deployment.yaml
replicas: 3
image: APP_IMAGE_URL
labels:
app: app-a
envFrom:
- configMapRef:
name: app-a-config
- secretRef:
name: app-a-secrets
ports:
- containerPort: 5000
resources:
cpu: 100m
memory: 300Mi
# ingress.yaml
host: app-a.example.com
backend:
serviceName: app-a-svc
servicePort: 5000
# service.yaml
metadata:
name: app-a-svc
spec:
type: ClusterIP
ports:
- port: 5000
targetPort: 5000
selector:
app: app-a$ kubectl apply -f <filename>.yamlhttp://app-a.example.com
node/vm
http://app-a-svc:5000
# configmap.yaml
metadata:
name: app-a-config
data:
MY_SERVICE_B: https://app-b.example.com
MY_SERVICE_C: https://app-c.example.com
MY_SERVICE_D: https://app-d.example.com
# secrets.yaml
metadata:
name: app-a-secrets
data:
FIREBASE_KEY: 611ff190-7fe1-4a71-ae75
GOOGLE_SECRET: $kILat8GKeUqoaGY8w34sgg
MAIL_API_KEY: f415aacd443eecd1634a59d
Environment variables
- sensitive key values pairs
- encrypted and stored
- Shouldn't be committed to git repo
- deployed manually using cli
- stored as plain text
- non sensitive key values pairs
- Can be committed to git repo
Config maps
$ kubectl apply -f secrets.yaml Secrets
# deployment.yaml
...
...
envFrom:
- configMapRef:
name: app-a-config
- secretRef:
name: app-a-secretsKustomize
.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ └── ingress.yamlKustomize is a cli tool to merge, add, remove or update k8s configuration
.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml# kustomization.yaml
kind: Kustomization
resources:
- deployment.yaml
- service.yaml
- configmap.yaml
- ingress.yaml
commonLabels:
app: app-a
$ kustomize build ./base > myapp.yaml
$ kubectl apply -f myapp.yaml $ kustomize build ./base | kubectl apply -f -PS: Remember to deploy secrets separately
name: Build and Deploy to K8s
on:
push:
branches:
- master
jobs:
build:
runs-on: ubuntu-latest
steps:
# Checkout repo
# Setup gcloud SDK
# Setup docker
# Setup kubectl
# Setup kustomize
- run: |-
docker build --tag "eu.gcr.io/myorg/app-a:$GITHUB_SHA" .
docker push "eu.gcr.io/myorg/app-a:$GITHUB_SHA"
- run: kustomize edit set image APP_IMAGE_URL="eu.gcr.io/myorg/app-a:$GITHUB_SHA"
- run: kustomize build base | kubectl apply -f -
Deploying via Github Actions
PR test apps
.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml $ kustomize build ./base | kubectl apply -f -.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml
├── pr
│ ├── deployment.yaml
│ └── ingress.yaml# ./pr/kustomization.yaml
bases:
- ../base
patchesStrategicMerge:
- deployment.yaml
- ingress.yaml
nameSuffix:
-pr-1
commonLabels:
pr: 1# ./pr/ingress.yaml
host: app-a-pr-1.example.com
backend:
serviceName: app-a-svc
servicePort: 5000
# ./pr/deployment.yaml
metadata:
name: app-a-deploy
spec:
replicas: 1 $ kustomize build ./pr | kubectl apply -f -.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml
├── pr
│ ├── deployment.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml// app-a-pr-1
.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml
├── pr
│ ├── deployment.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml# ./base/configmap.yaml
metadata:
name: app-a-config
data:
MY_SERVICE_B: https://app-b.example.com
MY_SERVICE_C: https://app-c.example.com
MY_SERVICE_D: https://app-d.example.com
Linking app-a-pr-1
app-b-pr-2
D
C
B
A
A
PR1
B
PR2
# ./base/configmap.yaml
metadata:
name: app-a-config
data:
- MY_SERVICE_B: https://app-b.example.com
+ MY_SERVICE_B: https://app-b-pr-2.example.com
MY_SERVICE_C: https://app-c.example.com
MY_SERVICE_D: https://app-d.example.com// app-a-pr-1
.
├── base
│ ├── deployment.yaml
│ ├── configmap.yaml
│ ├── service.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml
├── pr
│ ├── deployment.yaml
│ ├── ingress.yaml
│ └── kustomization.yaml# ./base/configmap.yaml
metadata:
name: app-a-config
data:
MY_SERVICE_B: https://app-b.example.com
MY_SERVICE_C: https://app-c.example.com
MY_SERVICE_D: https://app-d.example.com
Linking app-a-pr-1
app-b-pr-2
D
C
B
A
A
PR1
B
PR2
# ./base/configmap.yaml
metadata:
name: app-a-config
data:
- MY_SERVICE_B: https://app-b.example.com
+ MY_SERVICE_B: https://app-b-pr-2.example.com
MY_SERVICE_C: https://app-c.example.com
MY_SERVICE_D: https://app-d.example.comCleaning up
on:
pull_request:
types:
- closed
jobs:
cleanup:
runs-on: ubuntu-latest
steps:
# Checkout repo
# Setup gcloud SDK
# Setup kubectl
- run: |-
export PR_NUMBER=${{github.event.number}}
kubectl delete \
configmap,deployment,ingress,pods,replicasets,service \
-l app=app-a,pr=$PR_NUMBER
GitOps for Kubernetes using github actions
By Atul R
GitOps for Kubernetes using github actions
TechTree Show The Code | EQT Ventures Edition | 10th Dec 2020
