Restruct

12_orchestration/etcd/etcdctl.md

@@ -0,0 +1,152 @@
+## 使用 etcdctl
+
+`etcdctl` 是一个命令行客户端，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。这在某些情况下将很方便，例如用户对服务进行测试或者手动修改数据库内容。我们也推荐在刚接触 `etcd` 时通过 `etcdctl` 命令来熟悉相关的操作，这些操作跟 `HTTP API` 实际上是对应的。
+
+`etcd` 项目二进制发行包中已经包含了 `etcdctl` 工具，没有的话，可以从 [github.com/etcd-io/etcd/releases](https://github.com/etcd-io/etcd/releases) 下载。
+
+`etcdctl` 支持如下的命令，大体上分为数据库操作和非数据库操作两类，后面将分别进行解释。
+
+```
+NAME:
+	etcdctl - A simple command line client for etcd3.
+
+USAGE:
+	etcdctl
+
+VERSION:
+	3.4.0
+
+API VERSION:
+	3.4
+
+
+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
+	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 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
+      --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)
+```
+
+### 数据库操作
+
+数据库操作围绕对键值和目录的 CRUD （符合 REST 风格的一套操作：Create）完整生命周期的管理。
+
+etcd 在键的组织上采用了层次化的空间结构（类似于文件系统中目录的概念），用户指定的键可以为单独的名字，如 `testkey`，此时实际上放在根目录 `/` 下面，也可以为指定目录结构，如 `cluster1/node2/testkey`，则将创建相应的目录结构。
+
+>注：CRUD 即 Create, Read, Update, Delete，是符合 REST 风格的一套 API 操作。
+
+#### put
+
+运行以下命令：
+
+```bash
+$ etcdctl put /testdir/testkey "Hello world"
+OK
+```
+
+#### get
+
+获取指定键的值。例如
+
+```bash
+$ etcdctl put testkey hello
+OK
+$ etcdctl get testkey
+testkey
+hello
+```
+
+支持的选项为
+
+`--sort`	对结果进行排序
+
+`--consistent` 将请求发给主节点，保证获取内容的一致性
+
+#### del
+
+删除某个键值。例如
+
+```bash
+$ etcdctl del testkey
+1
+```
+
+### 非数据库操作
+
+#### watch
+
+监测一个键值的变化，一旦键值发生更新，就会输出最新的值。
+
+例如，用户更新 `testkey` 键值为 `Hello world`。
+
+```bash
+$ etcdctl watch testkey
+PUT
+testkey
+2
+```
+
+#### member
+
+通过 `list`、`add`、`update`、`remove` 命令列出、添加、更新、删除 etcd 实例到 etcd 集群中。
+
+例如本地启动一个 `etcd` 服务实例后，可以用如下命令进行查看。
+
+```bash
+$ etcdctl member list
+422a74f03b622fef, started, node1, http://172.16.238.100:2380, http://172.16.238.100:23
+```