Build git-sync for side car container in Kubernetes

Problem:

We have some config variables which can be updated some time by developers, so we need use this ENV variable in our container, how to update?

Solution:

As kubernetes we can create a pod with multiple containers. All containers can share volume (data). So we can use git to store data, every time code is pushed to gihub, the data will be pulled to volume by sidecar container.

let try with https://github.com/kubernetes/git-sync

How to use:

we assume there are 3 containers.

First is nginx which will be used for web server, second is hugo which will be used as static and git-sync which will pull source code from github every time new push.

1. using https

This case is simple but our git repo must be public.

Let create a pod with 3 containers

apiVersion: apps/v1
kind: Deployment
metadata:
  name: blog
spec:
  replicas: 1
  selector:
    matchLabels:
      name: blog
  template:
    metadata:
      labels:
        name: blog
    spec:
      containers:
      - name: git-sync
        image: k8s.gcr.io/git-sync:v3.0.1
        volumeMounts:
        - name: markdown
          mountPath: /tmp/git
        env:
        - name: GIT_SYNC_REPO
          value: https://github.com/kubernetes/git-sync.git
        - name: GIT_SYNC_DEST
          value: git-sync
      - name: hugo
        image: k8s.gcr.io/hugo
        volumeMounts:
        - name: markdown
          mountPath: /src
        - name: html
          mountPath: /dest
        env:
        - name: HUGO_SRC
          value: /src/git-sync/demo/blog
        - name: HUGO_BUILD_DRAFT
          value: "true"
        - name: HUGO_BASE_URL
          value: example.com
      - name: nginx
        image: nginx
        volumeMounts:
        - name: html
          mountPath: /usr/share/nginx/html
      volumes:
      - name: markdown
        emptyDir: {}
      - name: html
        emptyDir: {}

services file

apiVersion: v1
kind: Service
metadata:
  name: blog-service
spec:
  type: LoadBalancer
  ports:
  - port: 80
  selector:
    name: blog

2. Our repo is private

In this case, we need to add ssh key to GitHub and use public key to pull source from the git. It is quite complicated. I write next …