http-warmup-sidecar

What is this?

When we use JVM application on Kubernetes, we must warm up our application before real request sent.

This sidecar image perform following things:

send health check requests until main container stand up per second
send warm up requests
create /http-warmup/warmup-completed file

Parameters

all parameters are required.

number	parameter	example	if empty string
`$1`	url for health check	`localhost:3000`	`localhost:8080`
`$2`	http method for health check	`POST`	`GET`
`$3`	http header for health check	`Cookie: foobar`
`$4`	http body for health check	`{"foo": "bar"}`
`$5`	url for warmup	`localhost:3000`	`localhost:8080`
`$6`	http method for warmup	`POST`	`GET`
`$7`	http header for warmup	`Cookie: foobar`
`$8`	http body for warmup	`{"foo": "bar"}`
`$9`	count of requests for warmup	`1000`	`10`

Example to run on shell

 docker container run -t http-warmup:latest localhost:3000 "" "" "" localhost:3000 "" "" "" 10

Example of kubernetes manifest

apiVersion: apps/v1
kind: Deployment
spec:
  template:
    spec:
      containers:
        - name: warmup
          image: ghcr.io/miketako3/http-warmup-sidecar:latest
          args: [
            "localhost:8080",
            "",
            "",
            "",
            "localhost:8080",
            "",
            "",
            "",
            "10"
          ]
          readinessProbe:
            exec:
              command: [ "cat", "/http-warmup/warmup-completed" ]
            initialDelaySeconds: 30
            periodSeconds: 1
            failureThreshold: 10