k8s与configmap--安利configmap-reload组件

前言在kubernetes集群内，当ConfigMap以volume形式挂载到pod内时，更新ConfigMap，kubernetes会自动同步被挂载到pod内的文件内容。当然并不是更改立即生效的，大约是需要10S钟后，才会生效。实际生产使用案例中，假如你的应用具备hot reload 功能, 这时可以增加一些监测配置文件变更的脚本，然后reload对应服务。比如prometheus。今天就给大家介绍一个configmap-reload 组件。configmap-reloadconfigmap-reload 采用rust语言实现，作为主业务容器的sidercar，主要用于k8s当中监听configmap的变化，待变化后通过http接口的方式通知主业务。在资源消耗上，更小。具体如下：[root@ip-172-xx-xx-10 src]# kubectl top podsNAME CPU(cores) MEMORY(bytes)configmap-reload-6bbbb8b45b-7zg2x 0m 1Mi输入参数可以通过configmap-reload -h 获取：configmap-reload 0.1.0gaohj <gaohj2015@yeah.net>USAGE: configmap-reload [OPTIONS]FLAGS: -h, –help Prints help information -V, –version Prints version informationOPTIONS: -l, –log_level <LOG_LEVEL> log level: error|warn|info|debug|trace [default: info] -p, –path <VOLUME_PATH> the config map volume directory to watch for updates [default: ] -m, –webhook_method <WEBHOOK_METHOD> the HTTP method url to use to send the webhook: GET|POST [default: POST] -c, –webhook_status_code <WEBHOOK_STATUS_CODE> the HTTP status code indicating successful triggering of reload [default: 200] -u, –webhook_url <WEBHOOK_URL> the HTTP method url to use to send the webhook [default: ] 示例使用：—apiVersion: v1kind: ConfigMapmetadata: labels: app: configmap-reload name: configmap-reload-cmdata: test.ini: |- key: a—kind: DeploymentapiVersion: apps/v1metadata: name: configmap-reload labels: app: configmap-reloadspec: replicas: 1 selector: matchLabels: app: configmap-reload template: metadata: labels: app: configmap-reload spec: volumes: - name: config configMap: name: configmap-reload-cm containers: - name: configmap-reload image: ‘iyacontrol/configmap-reload:v0.1’ command: - configmap-reload args: - -l - debug - -p - /etc/test/ - -c - ‘200’ - -u - https://www.baidu.com volumeMounts: - name: config mountPath: /etc/test/ imagePullPolicy: Always—总结大家直接可以拉取 dockerhub 中的镜像。当然仓库中已经提供了Dockerfile文件，FROM clux/muslrust:stable as builderWORKDIR /configmap-reloadCOPY ./ ./ARG use_mirrorRUN if [ $use_mirror ]; then \ mkdir -p $HOME/.cargo; \ mv -f ./docker/cargo_config $HOME/.cargo/config; \ fiRUN cargo build –release#####################################FROM alpine:latest as prodRUN apk add –no-cache ca-certificates COPY –from=0 /configmap-reload/target/x86_64-unknown-linux-musl/release/configmap-reload /usr/bin/configmap-reloadRUN chmod +x /usr/bin/configmap-reloadENTRYPOINT [“configmap-reload”]大家可以自己打镜像，然后push到自己的仓库中。