Kubernetes中Nginx配置熱加載的全過程
前言
Nginx本身是支持熱更新的,通過nginx -s reload指令,實際通過向進程發送HUB信號實現不停服重新加載配置,然而在Docker或者Kubernetes中,每次都需要進容器執行nginx -s reload指令,單docker容器還好說,可以在外面通過exec指定容器執行該指令進行熱加載,Kubernetes的話,就比較難受瞭
今天介紹一下Kubernetes中Nginx熱加載配置的處理方法——reloader
reloader地址:https://github.com/stakater/Reloader
reloader主要就是用來監測ConfigMap或Secret的變化,然後對相關DeploymentConfig的Deployment、DaemonSet執行滾動升級
reloader需要kubernetes1.9以上的版本才支持
使用方法
首先是安裝部署reloader
# 直接通過官方yaml文件部署 kubectl apply -f https://raw.githubusercontent.com/stakater/Reloader/master/deployments/kubernetes/reloader.yaml
默認情況下reloader是部署在default命名空間,但是它是監控所有命名空間的configmaps和secrets
當然,如果不想監控某個configmap或secret,可以通過–resources-to-ignore=configMaps/secrets來忽略某個資源
部署成功後,就可以直接使用瞭,我提前部署瞭nginx和configmap
這是目前的配置,看一下Nginx目前的配置
接著,我修改Nginx的Deployment,添加reloader,監聽nginx-config這個ConfigMap,執行reload
{ "kind": "Deployment", "apiVersion": "extensions/v1beta1", "metadata": { "name": "nginx", "namespace": "default", "selfLink": "/apis/extensions/v1beta1/namespaces/default/deployments/nginx", "uid": "7eee5fa8-7514-11ec-a916-0210d5e9ca3b", "resourceVersion": "286141", "generation": 10, "creationTimestamp": "2022-01-14T08:32:23Z", "labels": { "k8s-app": "nginx" }, "annotations": { "deployment.kubernetes.io/revision": "9", "description": "nginx應用" # 主要是這行 "reloader.stakater.com/reload": "nginx-config" } }, "spec": { "replicas": 1, "selector": { "matchLabels": { "k8s-app": "nginx" } } ……
然後apply該Deployment,之後我們去更新ConfigMap,更新nginx配置文件
更新完成,去掉proxy_redirect,然後去看nginx容器是否執行滾動更新
可以看到,nginx執行瞭滾動更新,接著看下nginx配置文件是否更新
這樣很簡單的通過reloader就可以實現Nginx的配置熱加載
除瞭這種方法,常見的方法還有使用sidecar,通過sidecar去做的話,需要自己寫監聽腳本,比較麻煩,但是有時候也相對靈活,這裡也附一個sidecar的python腳本
#!/usr/bin/env python # -*- encoding: utf8 -*- """ 需求:nginx配置文件變化,自動更新配置文件,類似nginx -s reload 實現: 1、用pyinotify實時監控nginx配置文件變化 2、如果配置文件變化,給系統發送HUP來reload nginx """ import os import re import pyinotify import logging from threading import Timer # Param LOG_PATH = "/root/python/log" CONF_PATHS = [ "/etc/nginx", ] DELAY = 5 SUDO = False RELOAD_COMMAND = "nginx -s reload" if SUDO: RELOAD_COMMAND = "sudo " + RELOAD_COMMAND # Log logger = logging.getLogger(__name__) logger.setLevel(level = logging.INFO) log_handler = logging.FileHandler(LOG_PATH) log_handler.setLevel(logging.INFO) log_formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s') log_handler.setFormatter(log_formatter) logger.addHandler(log_handler) # Reloader def reload_nginx(): os.system(RELOAD_COMMAND) logger.info("nginx is reloaded") t = Timer(DELAY, reload_nginx) def trigger_reload_nginx(pathname, action): logger.info("nginx monitor is triggered because %s is %s" % (pathname, action)) global t if t.is_alive(): t.cancel() t = Timer(DELAY, reload_nginx) t.start() else: t = Timer(DELAY, reload_nginx) t.start() events = pyinotify.IN_MODIFY | pyinotify.IN_CREATE | pyinotify.IN_DELETE watcher = pyinotify.WatchManager() watcher.add_watch(CONF_PATHS, events, rec=True, auto_add=True) class EventHandler(pyinotify.ProcessEvent): def process_default(self, event): if event.name.endswith(".conf"): if event.mask == pyinotify.IN_CREATE: action = "created" if event.mask == pyinotify.IN_MODIFY: action = "modified" if event.mask == pyinotify.IN_DELETE: action = "deleted" trigger_reload_nginx(event.pathname, action) handler = EventHandler() notifier = pyinotify.Notifier(watcher, handler) # Start logger.info("Start Monitoring") notifier.loop()
如果喜歡用go的,這裡也提供go腳本
package main import ( "log" "os" "path/filepath" "syscall" "github.com/fsnotify/fsnotify" proc "github.com/shirou/gopsutil/process" ) const ( nginxProcessName = "nginx" defaultNginxConfPath = "/etc/nginx" watchPathEnvVarName = "WATCH_NGINX_CONF_PATH" ) var stderrLogger = log.New(os.Stderr, "error: ", log.Lshortfile) var stdoutLogger = log.New(os.Stdout, "", log.Lshortfile) func getMasterNginxPid() (int, error) { processes, processesErr := proc.Processes() if processesErr != nil { return 0, processesErr } nginxProcesses := map[int32]int32{} for _, process := range processes { processName, processNameErr := process.Name() if processNameErr != nil { return 0, processNameErr } if processName == nginxProcessName { ppid, ppidErr := process.Ppid() if ppidErr != nil { return 0, ppidErr } nginxProcesses[process.Pid] = ppid } } var masterNginxPid int32 for pid, ppid := range nginxProcesses { if ppid == 0 { masterNginxPid = pid break } } stdoutLogger.Println("found master nginx pid:", masterNginxPid) return int(masterNginxPid), nil } func signalNginxReload(pid int) error { stdoutLogger.Printf("signaling master nginx process (pid: %d) -> SIGHUP\n", pid) nginxProcess, nginxProcessErr := os.FindProcess(pid) if nginxProcessErr != nil { return nginxProcessErr } return nginxProcess.Signal(syscall.SIGHUP) } func main() { watcher, watcherErr := fsnotify.NewWatcher() if watcherErr != nil { stderrLogger.Fatal(watcherErr) } defer watcher.Close() done := make(chan bool) go func() { for { select { case event, ok := <-watcher.Events: if !ok { return } if event.Op&fsnotify.Create == fsnotify.Create { if filepath.Base(event.Name) == "..data" { stdoutLogger.Println("config map updated") nginxPid, nginxPidErr := getMasterNginxPid() if nginxPidErr != nil { stderrLogger.Printf("getting master nginx pid failed: %s", nginxPidErr.Error()) continue } if err := signalNginxReload(nginxPid); err != nil { stderrLogger.Printf("signaling master nginx process failed: %s", err) } } } case err, ok := <-watcher.Errors: if !ok { return } stderrLogger.Printf("received watcher.Error: %s", err) } } }() pathToWatch, ok := os.LookupEnv(watchPathEnvVarName) if !ok { pathToWatch = defaultNginxConfPath } stdoutLogger.Printf("adding path: `%s` to watch\n", pathToWatch) if err := watcher.Add(pathToWatch); err != nil { stderrLogger.Fatal(err) } <-done }
ok,今天的內容就到這裡
總結
到此這篇關於Kubernetes中Nginx配置熱加載的文章就介紹到這瞭,更多相關Kubernetes中Nginx配置熱加載內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet!
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