14. 一文快速学懂常用工具——etcdctl 命令

本章讲解知识点

• 前言
• etcdctl 介绍
• etcdctl 命令

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1. 前言

Etcd 在微服务和Kubernates集群中不仅可以作为服务注册与发现，还可以作为 key-value 存储的中间件。

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2. etcdctl 介绍

etcdctl 是一个命令行的客户端，它能提供一些简洁的命令，供用户直接跟 etcd 服务打交道，而无需基于 HTTP API 方式。方便对服务进行测试或者手动修改数据库内容。

我们刚开始可以通过 etdctl 来熟悉相关操作。这些操作跟 HTTP API 基本上是对应的。etcdctl 在两个不同的 etcd 版本下的行为方式也完全不同。

export ETCDCTL_API=2
export ETCDCTL_API=3

本文主要以 API 3 为主。Etcd 二进制发行包中已经包含了etcdctl工具。

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3. etcdctl 命令

3.1. 查看Etcd版本的命令

# etcd --version
etcd Version: 3.5.4
Git SHA: 08407ff76
Go Version: go1.16.15
Go OS/Arch: linux/amd64

3.2. 查看 etcdctl 常用的命令

# etcdctl h
NAME:
        etcdctl - A simple command line client for etcd3.

USAGE:
        etcdctl [flags]

VERSION:
        3.5.4

API VERSION:
        3.5

COMMANDS:
        alarm disarm            Disarms all alarms
        alarm list              Lists all alarms
        auth disable            Disables authentication
        auth enable             Enables authentication
        auth status             Returns authentication status
        check datascale         Check the memory usage of holding data for different workloads on a given server endpoint.
        check perf              Check the performance of the etcd cluster
        compaction              Compacts the event history in etcd
        defrag                  Defragments the storage of the etcd members with given endpoints
        del                     Removes the specified key or range of keys [key, range_end)
        elect                   Observes and participates in leader election
        endpoint hashkv         Prints the KV history hash for each endpoint in --endpoints
        endpoint health         Checks the healthiness of endpoints specified in `--endpoints` flag
        endpoint status         Prints out the status of endpoints specified in `--endpoints` flag
        get                     Gets the key or a range of keys
        help                    Help about any command
        lease grant             Creates leases
        lease keep-alive        Keeps leases alive (renew)
        lease list              List all active leases
        lease revoke            Revokes leases
        lease timetolive        Get lease information
        lock                    Acquires a named lock
        make-mirror             Makes a mirror at the destination etcd cluster
        member add              Adds a member into the cluster
        member list             Lists all members in the cluster
        member promote          Promotes a non-voting member in the cluster
        member remove           Removes a member from the cluster
        member update           Updates a member in the cluster
        move-leader             Transfers leadership to another etcd cluster member.
        put                     Puts the given key into the store
        role add                Adds a new role
        role delete             Deletes a role
        role get                Gets detailed information of a role
        role grant-permission   Grants a key to a role
        role list               Lists all roles
        role revoke-permission  Rev