Kubernetes：etcdctl3的常用命令
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。
#!/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etcdctlv3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。
etcdctl --endpoints=http://172.16.5.4:12379 member list -w table
+-----------------+---------+-------+------------------------+-----------------------------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+-----------------+---------+-------+------------------------+-----------------------------------------------+
| c856d92a82ba66a | started | etcd0 | http://172.16.5.4:2380 | http://172.16.5.4:2379,http://172.16.5.4:4001 |
+-----------------+---------+-------+------------------------+-----------------------------------------------+
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