Kubernetes：etcdctl3的常用命令

╰半橙微兮° 2023-06-22 07:25 7阅读 0赞

> `etcdctl`的`v3`版本与`v2`版本使用命令有所不同，本文介绍`etcdctl v3`版本的命令工具的使用方式。

# 1. etcdctl的安装 #

`etcdctl`的二进制文件可以在 [github.com/coreos/etcd/releases][github.com_coreos_etcd_releases] 选择对应的版本下载，例如可以执行以下`install_etcdctl.sh`的脚本，修改其中的版本信息。

#!/bin/bash
    ETCD_VER=v3.3.4
    ETCD_DIR=etcd-download
    DOWNLOAD_URL=https://github.com/coreos/etcd/releases/download
    
    # Download
    mkdir ${ETCD_DIR}
    cd ${ETCD_DIR}
    wget ${DOWNLOAD_URL}/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz 
    tar -xzvf etcd-${ETCD_VER}-linux-amd64.tar.gz
    
    # install
    cd etcd-${ETCD_VER}-linux-amd64
    cp etcdctl /usr/local/bin/

# 2. etcdctl V3 #

使用`etcdctl`v3的版本时，需设置环境变量`ETCDCTL_API=3`。

export ETCDCTL_API=3
    
    或者在`/etc/profile`文件中添加环境变量
    vi /etc/profile
    ...
    export ETCDCTL_API=3
    ...
    source /etc/profile

查看当前etcdctl的版本信息`etcdctl version`。

[root@k8s-dbg-master-1 etcd]# etcdctl version
    etcdctl version: 3.3.4
    API version: 3.3

更多命令帮助可以查询`etcdctl —help`。

[root@k8s-dbg-master-1 etcd]# etcdctl --help
    NAME:
    	etcdctl - A simple command line client for etcd3.
    
    USAGE:
    	etcdctl
    
    VERSION:
    	3.3.4
    
    API VERSION:
    	3.3
    
    
    COMMANDS:
    	get			Gets the key or a range of keys
    	put			Puts the given key into the store
    	del			Removes the specified key or range of keys [key, range_end)
    	txn			Txn processes all the requests in one transaction
    	compaction		Compacts the event history in etcd
    	alarm disarm		Disarms all alarms
    	alarm list		Lists all alarms
    	defrag			Defragments the storage of the etcd members with given endpoints
    	endpoint health		Checks the healthiness of endpoints specified in `--endpoints` flag
    	endpoint status		Prints out the status of endpoints specified in `--endpoints` flag
    	endpoint hashkv		Prints the KV history hash for each endpoint in --endpoints
    	move-leader		Transfers leadership to another etcd cluster member.
    	watch			Watches events stream on keys or prefixes
    	version			Prints the version of etcdctl
    	lease grant		Creates leases
    	lease revoke		Revokes leases
    	lease timetolive	Get lease information
    	lease list		List all active leases
    	lease keep-alive	Keeps leases alive (renew)
    	member add		Adds a member into the cluster
    	member remove		Removes a member from the cluster
    	member update		Updates a member in the cluster
    	member list		Lists all members in the cluster
    	snapshot save		Stores an etcd node backend snapshot to a given file
    	snapshot restore	Restores an etcd member snapshot to an etcd directory
    	snapshot status		Gets backend snapshot status of a given file
    	make-mirror		Makes a mirror at the destination etcd cluster
    	migrate			Migrates keys in a v2 store to a mvcc store
    	lock			Acquires a named lock
    	elect			Observes and participates in leader election
    	auth enable		Enables authentication
    	auth disable		Disables authentication
    	user add		Adds a new user
    	user delete		Deletes a user
    	user get		Gets detailed information of a user
    	user list		Lists all users
    	user passwd		Changes password of user
    	user grant-role		Grants a role to a user
    	user revoke-role	Revokes a role from a user
    	role add		Adds a new role
    	role delete		Deletes a role
    	role get		Gets detailed information of a role
    	role list		Lists all roles
    	role grant-permission	Grants a key to a role
    	role revoke-permission	Revokes a key from a role
    	check perf		Check the performance of the etcd cluster
    	help			Help about any command
    
    OPTIONS:
          --cacert=""				verify certificates of TLS-enabled secure servers using this CA bundle
          --cert=""					identify secure client using this TLS certificate file
          --command-timeout=5s			timeout for short running command (excluding dial timeout)
          --debug[=false]				enable client-side debug logging
          --dial-timeout=2s				dial timeout for client connections
      -d, --discovery-srv=""			domain name to query for SRV records describing cluster endpoints
          --endpoints=[127.0.0.1:2379]		gRPC endpoints
          --hex[=false]				print byte strings as hex encoded strings
          --insecure-discovery[=true]		accept insecure SRV records describing cluster endpoints
          --insecure-skip-tls-verify[=false]	skip server certificate verification
          --insecure-transport[=true]		disable transport security for client connections
          --keepalive-time=2s			keepalive time for client connections
          --keepalive-timeout=6s			keepalive timeout for client connections
          --key=""					identify secure client using this TLS key file
          --user=""					username[:password] for authentication (prompt if password is not supplied)
      -w, --write-out="simple"			set the output format (fields, json, protobuf, simple, table)

# 3. etcdctl 常用命令 #

## 3.1. 指定etcd集群 ##

HOST_1=10.240.0.17
    HOST_2=10.240.0.18
    HOST_3=10.240.0.19
    ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
    
    etcdctl --endpoints=$ENDPOINTS member list

## 3.2. 增删改查 ##

**1、增**

etcdctl --endpoints=$ENDPOINTS put foo "Hello World!"

**2、查**

etcdctl --endpoints=$ENDPOINTS get foo
    etcdctl --endpoints=$ENDPOINTS --write-out="json" get foo

基于相同前缀查找

etcdctl --endpoints=$ENDPOINTS put web1 value1
    etcdctl --endpoints=$ENDPOINTS put web2 value2
    etcdctl --endpoints=$ENDPOINTS put web3 value3
    
    etcdctl --endpoints=$ENDPOINTS get web --prefix

列出所有的key

etcdctl --endpoints=$ENDPOINTS get / --prefix --keys-only

3、**删**

etcdctl --endpoints=$ENDPOINTS put key myvalue
    etcdctl --endpoints=$ENDPOINTS del key
    
    etcdctl --endpoints=$ENDPOINTS put k1 value1
    etcdctl --endpoints=$ENDPOINTS put k2 value2
    etcdctl --endpoints=$ENDPOINTS del k --prefix

## 3.3. 集群状态 ##

集群状态主要是`etcdctl endpoint status` 和`etcdctl endpoint health`两条命令。

etcdctl --write-out=table --endpoints=$ENDPOINTS endpoint status
    
    +------------------+------------------+---------+---------+-----------+-----------+------------+
    |     ENDPOINT     |        ID        | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
    +------------------+------------------+---------+---------+-----------+-----------+------------+
    | 10.240.0.17:2379 | 4917a7ab173fabe7 | 3.0.0   | 45 kB   | true      |         4 |      16726 |
    | 10.240.0.18:2379 | 59796ba9cd1bcd72 | 3.0.0   | 45 kB   | false     |         4 |      16726 |
    | 10.240.0.19:2379 | 94df724b66343e6c | 3.0.0   | 45 kB   | false     |         4 |      16726 |
    +------------------+------------------+---------+---------+-----------+-----------+------------+
    
    etcdctl --endpoints=$ENDPOINTS endpoint health
    
    10.240.0.17:2379 is healthy: successfully committed proposal: took = 3.345431ms
    10.240.0.19:2379 is healthy: successfully committed proposal: took = 3.767967ms
    10.240.0.18:2379 is healthy: successfully committed proposal: took = 4.025451ms

## 3.4. 集群成员 ##

跟集群成员相关的命令如下：

member add		    Adds a member into the cluster
    	member remove		Removes a member from the cluster
    	member update		Updates a member in the cluster
    	member list		    Lists all members in the cluster

例如 `etcdctl member list`列出集群成员的命令。

# 4. etcdctl get #

使用`etcdctl {command} --help`可以查看具体命令的帮助信息。

# etcdctl get --help
    NAME:
    	get - Gets the key or a range of keys
    
    USAGE:
    	etcdctl get [options] <key> [range_end]
    
    OPTIONS:
          --consistency="l"			Linearizable(l) or Serializable(s)
          --from-key[=false]		Get keys that are greater than or equal to the given key using byte compare
          --keys-only[=false]		Get only the keys
          --limit=0				Maximum number of results
          --order=""			Order of results; ASCEND or DESCEND (ASCEND by default)
          --prefix[=false]			Get keys with matching prefix
          --print-value-only[=false]	Only write values when using the "simple" output format
          --rev=0				Specify the kv revision
          --sort-by=""			Sort target; CREATE, KEY, MODIFY, VALUE, or VERSION
    
    GLOBAL OPTIONS:
          --cacert=""				verify certificates of TLS-enabled secure servers using this CA bundle
          --cert=""					identify secure client using this TLS certificate file
          --command-timeout=5s			timeout for short running command (excluding dial timeout)
          --debug[=false]				enable client-side debug logging
          --dial-timeout=2s				dial timeout for client connections
          --endpoints=[127.0.0.1:2379]		gRPC endpoints
          --hex[=false]				print byte strings as hex encoded strings
          --insecure-skip-tls-verify[=false]	skip server certificate verification
          --insecure-transport[=true]		disable transport security for client connections
          --key=""					identify secure client using this TLS key file
          --user=""					username[:password] for authentication (prompt if password is not supplied)
      -w, --write-out="simple"			set the output format (fields, json, protobuf, simple, table)

文章参考：

https://coreos.com/etcd/docs/latest/demo.html

[github.com_coreos_etcd_releases]: https://github.com/coreos/etcd/releases