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 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。

  1. #!/bin/bash
  2. ETCD_VER=v3.3.4
  3. ETCD_DIR=etcd-download
  4. DOWNLOAD_URL=https://github.com/coreos/etcd/releases/download
  6. # Download
  7. mkdir ${ETCD_DIR}
  8. cd ${ETCD_DIR}
  9. wget ${DOWNLOAD_URL}/${ETCD_VER}/etcd-${ETCD_VER}-linux-amd64.tar.gz 
  10. tar -xzvf etcd-${ETCD_VER}-linux-amd64.tar.gz
  12. # install
  13. cd etcd-${ETCD_VER}-linux-amd64
  14. cp etcdctl /usr/local/bin/

2. etcdctl V3

使用etcdctlv3的版本时，需设置环境变量ETCDCTL_API=3。

  1. export ETCDCTL_API=3
  3. 或者在`/etc/profile`文件中添加环境变量
  4. vi /etc/profile
  5. ...
  6. ETCDCTL_API=3
  7. ...
  8. source /etc/profile

查看当前etcdctl的版本信息etcdctl version。

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

更多命令帮助可以查询etcdctl —help。

  1. [root@k8s-dbg-master-1 etcd]# etcdctl --help
  2. NAME:
  3.     etcdctl - A simple command line client for etcd3.
  5. USAGE:
  6.     etcdctl
  8. VERSION:
  9.     3.3.4
  11. API VERSION:
  12.     3.3
  15. COMMANDS:
  16.     get            Gets the key or a range of keys
  17.     put            Puts the given key into the store
  18.     del            Removes the specified key or range of keys [key, range_end)
  19.     txn            Txn processes all the requests in one transaction
  20.     compaction        Compacts the event history in etcd
  21.     alarm disarm        Disarms all alarms
  22.     alarm list        Lists all alarms
  23.     defrag            Defragments the storage of the etcd members with given endpoints
  24.     endpoint health        Checks the healthiness of endpoints specified in `--endpoints` flag
  25.     endpoint status        Prints out the status of endpoints specified in `--endpoints` flag
  26.     endpoint hashkv        Prints the KV history hash for each endpoint in --endpoints
  27.     move-leader        Transfers leadership to another etcd cluster member.
  28.     watch            Watches events stream on keys or prefixes
  29.     version            Prints the version of etcdctl
  30.     lease grant        Creates leases
  31.     lease revoke        Revokes leases
  32.     lease timetolive    Get lease information
  33.     lease list        List all active leases
  34.     lease keep-alive    Keeps leases alive (renew)
  35.     member add        Adds a member into the cluster
  36.     member remove        Removes a member from the cluster
  37.     member update        Updates a member in the cluster
  38.     member list        Lists all members in the cluster
  39.     snapshot save        Stores an etcd node backend snapshot to a given file
  40.     snapshot restore    Restores an etcd member snapshot to an etcd directory
  41.     snapshot status        Gets backend snapshot status of a given file
  42.     make-mirror        Makes a mirror at the destination etcd cluster
  43.     migrate            Migrates keys in a v2 store to a mvcc store
  44.     lock            Acquires a named lock
  45.     elect            Observes and participates in leader election
  46.     auth enable        Enables authentication
  47.     auth disable        Disables authentication
  48.     user add        Adds a new user
  49.     user delete        Deletes a user
  50.     user get        Gets detailed information of a user
  51.     user list        Lists all users
  52.     user passwd        Changes password of user
  53.     user grant-role        Grants a role to a user
  54.     user revoke-role    Revokes a role from a user
  55.     role add        Adds a new role
  56.     role delete        Deletes a role
  57.     role get        Gets detailed information of a role
  58.     role list        Lists all roles
  59.     role grant-permission    Grants a key to a role
  60.     role revoke-permission    Revokes a key from a role
  61.     check perf        Check the performance of the etcd cluster
  62.     help            Help about any command
  64. OPTIONS:
  65.       --cacert=""                verify certificates of TLS-enabled secure servers using this CA bundle
  66.       --cert=""                    identify secure client using this TLS certificate file
  67.       --command-timeout=5s            timeout for short running command (excluding dial timeout)
  68.       --debug[=false]                enable client-side debug logging
  69.       --dial-timeout=2s                dial timeout for client connections
  70.   -d, --discovery-srv=""            domain name to query for SRV records describing cluster endpoints
  71.       --endpoints=[127.0.0.1:2379]        gRPC endpoints
  72.       --hex[=false]                print byte strings as hex encoded strings
  73.       --insecure-discovery[=true]        accept insecure SRV records describing cluster endpoints
  74.       --insecure-skip-tls-verify[=false]    skip server certificate verification
  75.       --insecure-transport[=true]        disable transport security for client connections
  76.       --keepalive-time=2s            keepalive time for client connections
  77.       --keepalive-timeout=6s            keepalive timeout for client connections
  78.       --key=""                    identify secure client using this TLS key file
  79.       --user=""                    username[:password] for authentication (prompt if password is not supplied)
  80.   -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

  1. HOST_1=10.240.0.17
  2. HOST_2=10.240.0.18
  3. HOST_3=10.240.0.19
  4. ENDPOINTS=$HOST_1:2379,$HOST_2:2379,$HOST_3:2379
  6. etcdctl --endpoints=$ENDPOINTS member list

3.2. 增删改查

1、增

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

2、查

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

基于相同前缀查找

  1. etcdctl --endpoints=$ENDPOINTS put web1 value1
  2. etcdctl --endpoints=$ENDPOINTS put web2 value2
  3. etcdctl --endpoints=$ENDPOINTS put web3 value3
  5. etcdctl --endpoints=$ENDPOINTS get web --prefix

列出所有的key

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

3、删**

  1. etcdctl --endpoints=$ENDPOINTS put key myvalue
  2. etcdctl --endpoints=$ENDPOINTS del key
  4. etcdctl --endpoints=$ENDPOINTS put k1 value1
  5. etcdctl --endpoints=$ENDPOINTS put k2 value2
  6. 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。

  1. etcdctl --write-out=table --endpoints=$ENDPOINTS endpoint status
  3. +------------------+------------------+---------+---------+-----------+-----------+------------+
  4. |     ENDPOINT     |        ID        | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
  5. +------------------+------------------+---------+---------+-----------+-----------+------------+
  6. | 10.240.0.17:2379 | 4917a7ab173fabe7 | 3.0.0   | 45 kB   | true      |         4 |      16726 |
  7. | 10.240.0.18:2379 | 59796ba9cd1bcd72 | 3.0.0   | 45 kB   | false     |         4 |      16726 |
  8. | 10.240.0.19:2379 | 94df724b66343e6c | 3.0.0   | 45 kB   | false     |         4 |      16726 |
  9. +------------------+------------------+---------+---------+-----------+-----------+------------+
  11. etcdctl --endpoints=$ENDPOINTS endpoint health
  13. 10.240.0.17:2379 is healthy: successfully committed proposal: took = 3.345431ms
  14. 10.240.0.19:2379 is healthy: successfully committed proposal: took = 3.767967ms
  15. 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：

  1.     member add            Adds a member into the cluster
  2.     member remove        Removes a member from the cluster
  3.     member update        Updates a member in the cluster
  4.     member list            Lists all members in the cluster

例如 etcdctl member list列出集群成员的命令。

  1. etcdctl --endpoints=http://172.16.5.4:12379 member list -w table
  3. +-----------------+---------+-------+------------------------+-----------------------------------------------+
  4. |       ID        | STATUS  | NAME  |       PEER ADDRS       |                 CLIENT ADDRS                  |
  5. +-----------------+---------+-------+------------------------+-----------------------------------------------+
  6. | c856d92a82ba66a | started | etcd0 | http://172.16.5.4:2380 | http://172.16.5.4:2379,http://172.16.5.4:4001 |
  7. +-----------------+---------+-------+------------------------+-----------------------------------------------+

4. etcdctl get

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

  1. # etcdctl get --help
  2. NAME:
  3.     get - Gets the key or a range of keys
  5. USAGE:
  6.     etcdctl get [options] <key> [range_end]
  8. OPTIONS:
  9.       --consistency="l"            Linearizable(l) or Serializable(s)
  10.       --from-key[=false]        Get keys that are greater than or equal to the given key using byte compare
  11.       --keys-only[=false]        Get only the keys
  12.       --limit=0                Maximum number of results
  13.       --order=""            Order of results; ASCEND or DESCEND (ASCEND by default)
  14.       --prefix[=false]            Get keys with matching prefix
  15.       --print-value-only[=false]    Only write values when using the "simple" output format
  16.       --rev=0                Specify the kv revision
  17.       --sort-by=""            Sort target; CREATE, KEY, MODIFY, VALUE, or VERSION
  19. GLOBAL OPTIONS:
  20.       --cacert=""                verify certificates of TLS-enabled secure servers using this CA bundle
  21.       --cert=""                    identify secure client using this TLS certificate file
  22.       --command-timeout=5s            timeout for short running command (excluding dial timeout)
  23.       --debug[=false]                enable client-side debug logging
  24.       --dial-timeout=2s                dial timeout for client connections
  25.       --endpoints=[127.0.0.1:2379]        gRPC endpoints
  26.       --hex[=false]                print byte strings as hex encoded strings
  27.       --insecure-skip-tls-verify[=false]    skip server certificate verification
  28.       --insecure-transport[=true]        disable transport security for client connections
  29.       --key=""                    identify secure client using this TLS key file
  30.       --user=""                    username[:password] for authentication (prompt if password is not supplied)
  31.   -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