一、什么是etcd
Etcd是一种分布式键值对数据库,是由CoreOS开发的开源软件,在Kubernetes、OpenStack等众多云计算平台上都被广泛应用。Etcd采用Go语言编写,提供了一种可靠的方式来存储一些关键的数据,并且可以通过RESTful API方便地访问和修改这些数据。Etcd在一个集群中维护了多个节点,所有节点都是平等的,支持读写分离和多租户,同时也支持快照和复制等功能。
二、为什么需要可视化工具
Etcd提供了一个可靠高效的存储方式,但是对于用户来说,直接在命令行维护和管理Etcd还是比较麻烦的,特别是在集群规模变大之后。因此,一些第三方开发者和组织提供了一些可视化的工具来方便管理和维护Etcd。
三、etcd可视化工具介绍
1. Etcd Web
Etcd Web是一个基于Web界面的Etcd管理工具,它提供了一套可视化的交互界面,使得开发者可以方便地查看和修改Etcd中的数据,以及进行用户管理和集群状态管理等操作。Etcd Web基于AngularJS和Bootstrap开发,并且使用了Restful接口来与Etcd集群进行通讯。
<!-- etcd web代码示例 -->
<!DOCTYPE html>
<html ng-app="etcdWebApp">
<head>
<title>Etcd Web</title>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css" rel="stylesheet" type="text/css" />
<link href="//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css" rel="stylesheet" type="text/css" />
<link href="https://cdnjs.cloudflare.com/ajax/libs/angular-ui-tree/2.22.5/angular-ui-tree.min.css" rel="stylesheet" />
<link href="css/app.css" rel="stylesheet" type="text/css" />
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.26/angular.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.26/angular-route.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.26/angular-animate.min.js"></script>
<script src="//angular-ui.github.io/bootstrap/ui-bootstrap-tpls-0.11.2.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-ui-tree/2.22.5/angular-ui-tree.min.js"></script>
<script src="js/app.js"></script>
</head>
<body ng-controller="mainController">
<div class="navbar navbar-default navbar-fixed-top" role="navigation">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Etcd Web</a>
</div>
<div class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li ng-class="{ active: isRootPath() }"><a ng-href="/">Home</a></li>
<li ng-class="{ active: isNodePath() }"><a ng-href="#!/nodes">Nodes</a></li>
<li ng-class="{ active: isConfigPath() }"><a ng-href="#!/config">Config</a></li>
<li ng-class="{ active: isUsersPath() }"><a ng-href="#!/users">Users</a></li>
<li ng-class="{ active: isStatusPath() }"><a ng-href="#!/status">Status</a></li>
</ul>
</div>
</div>
</div>
<div ng-view></div>
</body>
</html>
2. Etcd-UI
Etcd-UI是一个基于Web界面的Etcd管理工具,它提供了多种视图方式来查看和修改Etcd中的数据,支持直接操作JSON格式的数据,同时也支持折叠式视图和树形视图等操作。Etcd-UI使用Go语言编写,并且提供了跨平台的可执行文件和Docker镜像。
// etcd-UI代码示例
package main
import (
"net/http"
"net/url"
"github.com/coreos/etcd/client"
"github.com/coreos/etcd/clientv3"
"go.etcd.io/etcd/clientv3/concurrency"
"go.etcd.io/etcd/clientv3/namespace"
"go.etcd.io/etcd/clientv3/naming/endpoints"
"go.etcd.io/etcd/clientv3/txn"
)
func main() {
// connect to etcd
endpoints, err := endpoints.NewEndpoints("http://127.0.0.1:2379")
if err != nil {
log.Fatal(err)
}
cfg := clientv3.Config{
Endpoints: []string{"http://127.0.0.1:2379"},
}
c, err := clientv3.New(cfg)
if err != nil {
log.Fatal(err)
}
kvs := client.NewKeysAPI(c)
kv := clientv3.NewKV(c)
lease := clientv3.NewLease(c)
watch := clientv3.NewWatcher(c)
txn := clientv3.NewKV(c).Txn(context.Background())
// create a mutex
session, err := concurrency.NewSession(c)
if err != nil {
log.Fatal(err)
}
mutex := concurrency.NewMutex(session, "/my_lock")
// use a namespace
ns := namespace.NewKV(clientv3.NewKV(c), "/my_prefix")
// use a transaction
txn.If(
clientv3.Compare(clientv3.Value("key"), "=", "old_value"),
).Then(
clientv3.OpPut("key", "new_value"),
).Else(
clientv3.OpGet("key"),
)
// watch a key
watcher := watch.Watch(context.Background(), "key", clientv3.WithPrefix())
// grant a lease
resp, err := lease.Grant(context.Background(), 10)
if err != nil {
log.Fatal(err)
}
leaseID := resp.ID
// write to etcd
_, err = kvs.Set(context.Background(), "key", "value", nil)
if err != nil {
log.Fatal(err)
}
// read from etcd
resp, err = kvs.Get(context.Background(), "key", nil)
if err != nil {
log.Fatal(err)
}
for _, pair := range resp.Node.Nodes {
log.Printf("%s: %s\n", pair.Key, pair.Value)
}
// use a transaction
_, err = kv.Txn(context.Background()).If(
clientv3.Compare(clientv3.CreateRevision("key"), ">", 0),
).Then(
clientv3.OpGet("key"),
).Commit()
if err != nil {
log.Fatal(err)
}
// revoke a lease
_, err = lease.Revoke(context.Background(), leaseID)
if err != nil {
log.Fatal(err)
}
}
3. Heptio Gimbal
Heptio Gimbal是一种初级的代理负载均衡器,它使用etcd作为后端存储来管理和维护代理规则和服务发现等功能。Gimbal支持HTTP请求的负载均衡和路由,可以在多个集群之间进行负载均衡,并且支持HTTPS Termination。
# Heptio Gimbal代码示例
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: gimbal-proxy
spec:
replicas: 1
template:
metadata:
labels:
app: gimbal-proxy
spec:
containers:
- name: proxy
image: heptio/gimbal-proxy:0.2.1
args: ["--config", "/etc/gimbal/config.yaml"]
volumeMounts:
- name: config-volume
mountPath: /etc/gimbal/
ports:
- name: http
containerPort: 80
- name: https
containerPort: 443
resources:
requests:
cpu: 100m
memory: 256Mi
volumes:
- name: config-volume
configMap:
name: gimbal-proxy-config
items:
- key: config.yaml
path: config.yaml
---
apiVersion: v1
kind: ConfigMap
metadata:
name: gimbal-proxy-config
data:
config.yaml: |
services:
- name: serviceA
protocol: http
endpoints:
- labelSelector:
matchLabels:
app: serviceA
port: 8080
- name: serviceB
protocol: http
endpoints:
- labelSelector:
matchLabels:
app: serviceB
port: 9090
listeners:
- name: http
protocol: http
bindAddr: ":80"
routes:
- prefix: /serviceA
service: serviceA
- prefix: /serviceB
service: serviceB
- name: https
protocol: http
bindAddr: ":443"
certPath: /etc/gimbal/certs/tls.crt
keyPath: /etc/gimbal/certs/tls.key
routes:
- prefix: /serviceA
service: serviceA
- prefix: /serviceB
service: serviceB
四、结论
Etcd可视化工具的出现,极大地方便了Etcd集群的管理和维护,开发者可以根据自己的需求选择不同的工具,以方便更加高效地进行Etcd开发和调试。