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etcdctl: v3 as default README
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etcdctl
========
`etcdctl` is a command line client for [etcd][etcd].
It can be used in scripts or for administrators to explore an etcd cluster.
## Getting etcdctl
The latest release is available as a binary at [Github][github-release] along with etcd.
You can also build etcdctl from source using the build script found in the parent directory.
## Configuration
### --debug
+ output cURL commands which can be used to reproduce the request
### --no-sync
+ don't synchronize cluster information before sending request
+ Use this to access non-published client endpoints
+ Without this flag, values from `--endpoint` flag will be overwritten by etcd cluster when it does internal sync.
### --output, -o
+ output response in the given format (`simple`, `extended` or `json`)
+ default: `"simple"`
### --discovery-srv, -D
+ domain name to query for SRV records describing cluster endpoints
+ default: none
+ env variable: ETCDCTL_DISCOVERY_SRV
### --peers
+ a comma-delimited list of machine addresses in the cluster
+ default: `"http://127.0.0.1:2379"`
+ env variable: ETCDCTL_PEERS
### --endpoint
+ a comma-delimited list of machine addresses in the cluster
+ default: `"http://127.0.0.1:2379"`
+ env variable: ETCDCTL_ENDPOINT
+ Without `--no-sync` flag, this will be overwritten by etcd cluster when it does internal sync.
### --cert-file
+ identify HTTPS client using this SSL certificate file
+ default: none
+ env variable: ETCDCTL_CERT_FILE
### --key-file
+ identify HTTPS client using this SSL key file
+ default: none
+ env variable: ETCDCTL_KEY_FILE
### --ca-file
+ verify certificates of HTTPS-enabled servers using this CA bundle
+ default: none
+ env variable: ETCDCTL_CA_FILE
### --username, -u
+ provide username[:password] and prompt if password is not supplied
+ default: none
+ env variable: ETCDCTL_USERNAME
### --timeout
+ connection timeout per request
+ default: `"1s"`
### --total-timeout
+ timeout for the command execution (except watch)
+ default: `"5s"`
## Usage
### Setting Key Values
Set a value on the `/foo/bar` key:
```sh
$ etcdctl set /foo/bar "Hello world"
Hello world
```
Set a value on the `/foo/bar` key with a value that expires in 60 seconds:
```sh
$ etcdctl set /foo/bar "Hello world" --ttl 60
Hello world
```
Conditionally set a value on `/foo/bar` if the previous value was "Hello world":
```sh
$ etcdctl set /foo/bar "Goodbye world" --swap-with-value "Hello world"
Goodbye world
```
Conditionally set a value on `/foo/bar` if the previous etcd index was 12:
```sh
$ etcdctl set /foo/bar "Goodbye world" --swap-with-index 12
Goodbye world
```
Create a new key `/foo/bar`, only if the key did not previously exist:
```sh
$ etcdctl mk /foo/new_bar "Hello world"
Hello world
```
Create a new in-order key under dir `/fooDir`:
```sh
$ etcdctl mk --in-order /fooDir "Hello world"
```
Create a new dir `/fooDir`, only if the key did not previously exist:
```sh
$ etcdctl mkdir /fooDir
```
Update an existing key `/foo/bar`, only if the key already existed:
```sh
$ etcdctl update /foo/bar "Hola mundo"
Hola mundo
```
Create or update a directory called `/mydir`:
```sh
$ etcdctl setdir /mydir
```
### Retrieving a key value
Get the current value for a single key in the local etcd node:
```sh
$ etcdctl get /foo/bar
Hello world
```
Get the value of a key with additional metadata in a parseable format:
```sh
$ etcdctl -o extended get /foo/bar
Key: /foo/bar
Modified-Index: 72
TTL: 0
Etcd-Index: 72
Raft-Index: 5611
Raft-Term: 1
Hello World
```
### Listing a directory
Explore the keyspace using the `ls` command
```sh
$ etcdctl ls
/akey
/adir
$ etcdctl ls /adir
/adir/key1
/adir/key2
```
Add `--recursive` to recursively list subdirectories encountered.
```sh
$ etcdctl ls --recursive
/akey
/adir
/adir/key1
/adir/key2
```
Directories can also have a trailing `/` added to output using `-p`.
```sh
$ etcdctl ls -p
/akey
/adir/
```
### Deleting a key
Delete a key:
```sh
$ etcdctl rm /foo/bar
```
Delete an empty directory or a key-value pair
```sh
$ etcdctl rmdir /path/to/dir
```
or
```sh
$ etcdctl rm /path/to/dir --dir
```
Recursively delete a key and all child keys:
```sh
$ etcdctl rm /path/to/dir --recursive
```
Conditionally delete `/foo/bar` if the previous value was "Hello world":
```sh
$ etcdctl rm /foo/bar --with-value "Hello world"
```
Conditionally delete `/foo/bar` if the previous etcd index was 12:
```sh
$ etcdctl rm /foo/bar --with-index 12
```
### Watching for changes
Watch for only the next change on a key:
```sh
$ etcdctl watch /foo/bar
Hello world
```
Continuously watch a key:
```sh
$ etcdctl watch /foo/bar --forever
Hello world
.... client hangs forever until ctrl+C printing values as key change
```
Continuously watch a key, starting with a given etcd index:
```sh
$ etcdctl watch /foo/bar --forever --index 12
Hello world
.... client hangs forever until ctrl+C printing values as key change
```
Continuously watch a key and exec a program:
```sh
$ etcdctl exec-watch /foo/bar -- sh -c "env | grep ETCD"
ETCD_WATCH_ACTION=set
ETCD_WATCH_VALUE=My configuration stuff
ETCD_WATCH_MODIFIED_INDEX=1999
ETCD_WATCH_KEY=/foo/bar
ETCD_WATCH_ACTION=set
ETCD_WATCH_VALUE=My new configuration stuff
ETCD_WATCH_MODIFIED_INDEX=2000
ETCD_WATCH_KEY=/foo/bar
```
Continuously and recursively watch a key and exec a program:
```sh
$ etcdctl exec-watch --recursive /foo -- sh -c "env | grep ETCD"
ETCD_WATCH_ACTION=set
ETCD_WATCH_VALUE=My configuration stuff
ETCD_WATCH_MODIFIED_INDEX=1999
ETCD_WATCH_KEY=/foo/bar
ETCD_WATCH_ACTION=set
ETCD_WATCH_VALUE=My new configuration stuff
ETCD_WATCH_MODIFIED_INDEX=2000
ETCD_WATCH_KEY=/foo/barbar
```
## Return Codes
The following exit codes can be returned from etcdctl:
```
0 Success
1 Malformed etcdctl arguments
2 Failed to connect to host
3 Failed to auth (client cert rejected, ca validation failure, etc)
4 400 error from etcd
5 500 error from etcd
```
## Endpoint
If your etcd cluster isn't available on `http://127.0.0.1:2379` you can specify
a `--endpoint` flag or `ETCDCTL_ENDPOINT` environment variable. You can list one endpoint,
or a comma-separated list of endpoints. This option is ignored if the `--discovery-srv`
option is provided.
```sh
ETCDCTL_ENDPOINT="http://10.0.28.1:4002" etcdctl set my-key to-a-value
ETCDCTL_ENDPOINT="http://10.0.28.1:4002,http://10.0.28.2:4002,http://10.0.28.3:4002" etcdctl set my-key to-a-value
etcdctl --endpoint http://10.0.28.1:4002 my-key to-a-value
etcdctl --endpoint http://10.0.28.1:4002,http://10.0.28.2:4002,http://10.0.28.3:4002 etcdctl set my-key to-a-value
```
## Username and Password
If your etcd cluster is protected by [authentication][authentication], you can specify username and password using the [`--username`][username-flag] or `ETCDCTL_USERNAME` environment variable. When `--username` flag or `ETCDCTL_USERNAME` environment variable doesn't contain password, etcdctl will prompt password in interactive mode.
```sh
ETCDCTL_USERNAME="root:password" etcdctl set my-key to-a-value
```
## DNS Discovery
If you want to discover your etcd cluster through domain SRV records you can specify
a `--discovery-srv` flag or `ETCDCTL_DISCOVERY_SRV` environment variable. This option takes
precedence over the `--endpoint` flag.
```sh
ETCDCTL_DISCOVERY_SRV="some-domain" etcdctl set my-key to-a-value
etcdctl --discovery-srv some-domain set my-key to-a-value
```
## Project Details
### Versioning
etcdctl uses [semantic versioning][semver].
Releases will follow lockstep with the etcd release cycle.
### License
etcdctl is under the Apache 2.0 license. See the [LICENSE][license] file for details.
[authentication]: ../Documentation/v2/authentication.md
[etcd]: https://github.com/coreos/etcd
[github-release]: https://github.com/coreos/etcd/releases/
[license]: https://github.com/coreos/etcdctl/blob/master/LICENSE
[semver]: http://semver.org/
[username-flag]: #--username--u

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etcdctl
========
TODO: merge into README.md.
## Commands
### PUT [options] \<key\> \<value\>
PUT assigns the specified value with the specified key. If key already holds a value, it is overwritten.
#### Options
- lease -- lease ID (in hexadecimal) to attach to the key.
#### Return value
##### Simple reply
- OK if PUT executed correctly. Exit code is zero.
- Error string if PUT failed. Exit code is non-zero.
##### JSON reply
The JSON encoding of the PUT [RPC response][etcdrpc].
##### Protobuf reply
The protobuf encoding of the PUT [RPC response][etcdrpc].
#### Examples
``` bash
./etcdctl PUT foo bar --lease=0x1234abcd
OK
./etcdctl range foo
bar
```
#### Notes
If \<value\> isn't given as command line argument, this command tries to read the value from standard input.
When \<value\> begins with '-', \<value\> is interpreted as a flag.
Insert '--' for workaround:
``` bash
./etcdctl put <key> -- <value>
./etcdctl put -- <key> <value>
```
### GET [options] \<key\> [range_end]
GET gets the key or a range of keys [key, range_end) if `range-end` is given.
#### Options
- hex -- print out key and value as hex encode string
- limit -- maximum number of results
- prefix -- get keys by matching prefix
- order -- order of results; ASCEND or DESCEND
- sort-by -- sort target; CREATE, KEY, MODIFY, VALUE, or VERSION
- rev -- specify the kv revision
TODO: add consistency, from, prefix
#### Return value
##### Simple reply
- \<key\>\n\<value\>\n\<next_key\>\n\<next_value\>...
- Error string if GET failed. Exit code is non-zero.
##### JSON reply
The JSON encoding of the [RPC response][etcdrpc] for the GET's Range request.
##### Protobuf reply
The protobuf encoding of the [RPC message][etcdrpc] for a key-value pair for each fetched key-value.
#### Examples
``` bash
./etcdctl get foo
foo
bar
```
#### Notes
If any key or value contains non-printable characters or control characters, the output in text format (e.g. simple reply) might be ambiguous.
Adding `--hex` to print key or value as hex encode string in text format can resolve this issue.
### DEL [options] \<key\> [range_end]
Removes the specified key or range of keys [key, range_end) if `range-end` is given.
#### Options
- prefix -- delete keys by matching prefix
TODO: --from
#### Return value
##### Simple reply
- The number of keys that were removed in decimal if DEL executed correctly. Exit code is zero.
- Error string if DEL failed. Exit code is non-zero.
##### JSON reply
The JSON encoding of the DeleteRange [RPC response][etcdrpc].
##### Protobuf reply
The protobuf encoding of the DeleteRange [RPC response][etcdrpc].
#### Examples
``` bash
./etcdctl put foo bar
OK
./etcdctl del foo
1
./etcdctl range foo
```
### TXN [options]
TXN reads multiple etcd requests from standard input and applies them as a single atomic transaction.
A transaction consists of list of conditions, a list of requests to apply if all the conditions are true, and a list of requests to apply if any condition is false.
#### Options
- hex -- print out keys and values as hex encoded string
- interactive -- input transaction with interactive prompting
#### Input Format
```ebnf
<Txn> ::= <CMP>* "\n" <THEN> "\n" <ELSE> "\n"
<CMP> ::= (<CMPCREATE>|<CMPMOD>|<CMPVAL>|<CMPVER>) "\n"
<CMPOP> ::= "<" | "=" | ">"
<CMPCREATE> := ("c"|"create")"("<KEY>")" <REVISION>
<CMPMOD> ::= ("m"|"mod")"("<KEY>")" <CMPOP> <REVISION>
<CMPVAL> ::= ("val"|"value")"("<KEY>")" <CMPOP> <VALUE>
<CMPVER> ::= ("ver"|"version")"("<KEY>")" <CMPOP> <VERSION>
<THEN> ::= <OP>*
<ELSE> ::= <OP>*
<OP> ::= ((see put, get, del etcdctl command syntax)) "\n"
<KEY> ::= (%q formatted string)
<VALUE> ::= (%q formatted string)
<REVISION> ::= "\""[0-9]+"\""
<VERSION> ::= "\""[0-9]+"\""
```
#### Return value
##### Simple reply
- SUCCESS if etcd processed the transaction success list, FAILURE if etcd processed the transaction failure list.
- Simple reply for each command executed request list, each separated by a blank line.
- Additional error string if TXN failed. Exit code is non-zero.
##### JSON reply
The JSON encoding of the Txn [RPC response][etcdrpc].
##### Protobuf reply
The protobuf encoding of the Txn [RPC response][etcdrpc].
#### Examples
txn in interactive mode:
``` bash
./etcdctl txn -i
mod("key1") > "0"
put key1 "overwrote-key1"
put key1 "created-key1"
put key2 "some extra key"
FAILURE
OK
OK
```
txn in non-interactive mode:
```
./etcdctl txn <<<'mod("key1") > "0"
put key1 "overwrote-key1"
put key1 "created-key1"
put key2 "some extra key"
'
FAILURE
OK
OK
````
### WATCH [options] [key or prefix]
Watch watches events stream on keys or prefixes. The watch command runs until it encounters an error or is terminated by the user.
#### Options
- hex -- print out key and value as hex encode string
- interactive -- begins an interactive watch session
- prefix -- watch on a prefix if prefix is set.
- rev -- the revision to start watching. Specifying a revision is useful for observing past events.
#### Input Format
Input is only accepted for interactive mode.
```
watch [options] <key or prefix>\n
```
#### Return value
##### Simple reply
- \<event\>\n\<key\>\n\<value\>\n\<event\>\n\<next_key\>\n\<next_value\>\n...
- Additional error string if WATCH failed. Exit code is non-zero.
##### JSON reply
The JSON encoding of the [RPC message][storagerpc] for each received Event.
##### Protobuf reply
The protobuf encoding of the [RPC message][storagerpc] for each received Event.
#### Examples
##### Non-interactive
``` bash
./etcdctl watch foo
PUT
foo
bar
```
##### Interactive
``` bash
./etcdctl watch -i
watch foo
watch foo
PUT
foo
bar
PUT
foo
bar
```
### LEASE \<subcommand\>
LEASE provides commands for key lease management.
### LEASE GRANT \<ttl\>
LEASE GRANT creates a fresh lease with a server-selected time-to-live in seconds
greater than or equal to the requested TTL value.
#### Return value
- On success, prints a message with the granted lease ID.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl lease grant 10
lease 32695410dcc0ca06 granted with TTL(10s)
```
### LEASE REVOKE \<leaseID\>
LEASE REVOKE destroys a given lease, deleting all attached keys.
#### Return value
- On success, prints a message indicating the lease is revoked.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl lease revoke 32695410dcc0ca06
lease 32695410dcc0ca06 revoked
```
### LEASE KEEP-ALIVE \<leaseID\>
LEASE KEEP-ALIVE periodically refreshes a lease so it does not expire.
#### Return value
- On success, prints a message for every keep alive sent.
- On failure, returns a non-zero exit code if a keep-alive channel could not be established. Otherwise, prints a message indicating the lease is gone.
#### Example
```bash
/etcdctl lease keep-alive 32695410dcc0ca0
lease 32695410dcc0ca0 keepalived with TTL(100)
lease 32695410dcc0ca0 keepalived with TTL(100)
lease 32695410dcc0ca0 keepalived with TTL(100)
...
```
### MEMBER \<subcommand\>
MEMBER provides commands for managing etcd cluster membership.
### MEMBER ADD \<memberName\>
MEMBER ADD introduces a new member into the etcd cluster as a new peer.
#### Options
- peerURLs -- comma separated list of URLs to associate with the new member.
#### Return value
- On success, prints the member ID of the new member and the cluster ID.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl member add newMember --peerURLs=https://127.0.0.1:12345
Member 2be1eb8f84b7f63e added to cluster ef37ad9dc622a7c4
```
### MEMBER UPDATE \<memberID\>
MEMBER UPDATE sets the peer URLs for an existing member in the etcd cluster.
#### Options
- peerURLs -- comma separated list of URLs to associate with the updated member.
#### Return value
- On success, prints the member ID of the updated member and the cluster ID.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl member update 2be1eb8f84b7f63e --peerURLs=https://127.0.0.1:11112
Member 2be1eb8f84b7f63e updated in cluster ef37ad9dc622a7c4
```
### MEMBER REMOVE \<memberID\>
MEMBER REMOVE removes a member of an etcd cluster from participating in cluster consensus.
#### Return value
- On success, prints the member ID of the removed member and the cluster ID.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl member remove 2be1eb8f84b7f63e
Member 2be1eb8f84b7f63e removed from cluster ef37ad9dc622a7c4
```
### MEMBER LIST
MEMBER LIST prints the member details for all members associated with an etcd cluster.
#### Return value
##### Simple reply
On success, prints a humanized table of the member IDs, statuses, names, peer addresses, and client addresses. On failure, prints an error message and returns with a non-zero exit code.
##### JSON reply
On success, prints a JSON listing of the member IDs, statuses, names, peer addresses, and client addresses. On failure, prints an error message and returns with a non-zero exit code.
##### Protobuf reply
The protobuf encoding of the MEMBER LIST [RPC response][member_list_rpc].
#### Examples
```bash
./etcdctl member list
8211f1d0f64f3269, started, infra1, http://127.0.0.1:12380, http://127.0.0.1:2379
91bc3c398fb3c146, started, infra2, http://127.0.0.1:22380, http://127.0.0.1:22379
fd422379fda50e48, started, infra3, http://127.0.0.1:32380, http://127.0.0.1:32379
```
```bash
./etcdctl -w json member list
{"header":{"cluster_id":17237436991929493444,"member_id":9372538179322589801,"raft_term":2},"members":[{"ID":9372538179322589801,"name":"infra1","peerURLs":["http://127.0.0.1:12380"],"clientURLs":["http://127.0.0.1:2379"]},{"ID":10501334649042878790,"name":"infra2","peerURLs":["http://127.0.0.1:22380"],"clientURLs":["http://127.0.0.1:22379"]},{"ID":18249187646912138824,"name":"infra3","peerURLs":["http://127.0.0.1:32380"],"clientURLs":["http://127.0.0.1:32379"]}]}
```
```bash
./etcdctl -w table member list
+------------------+---------+--------+------------------------+------------------------+
| ID | STATUS | NAME | PEER ADDRS | CLIENT ADDRS |
+------------------+---------+--------+------------------------+------------------------+
| 8211f1d0f64f3269 | started | infra1 | http://127.0.0.1:12380 | http://127.0.0.1:2379 |
| 91bc3c398fb3c146 | started | infra2 | http://127.0.0.1:22380 | http://127.0.0.1:22379 |
| fd422379fda50e48 | started | infra3 | http://127.0.0.1:32380 | http://127.0.0.1:32379 |
+------------------+---------+--------+------------------------+------------------------+
```
## Utility Commands
### ENDPOINT \<subcommand\>
ENDPOINT provides commands for querying individual endpoints.
### ENDPOINT HEALTH
ENDPOINT HEALTH checks the health of the list of endpoints with respect to cluster. An endpoint is unhealthy
when it cannot participate in consensus with the rest of the cluster.
#### Return value
- If an endpoint can participate in consensus, prints a message indicating the endpoint is healthy.
- If an endpoint fails to participate in consensus, prints a message indicating the endpoint is unhealthy.
#### Example
```bash
./etcdctl endpoint health
127.0.0.1:32379 is healthy: successfully committed proposal: took = 2.130877ms
127.0.0.1:2379 is healthy: successfully committed proposal: took = 2.095242ms
127.0.0.1:22379 is healthy: successfully committed proposal: took = 2.083263ms
```
### ENDPOINT STATUS
ENDPOINT STATUS queries the status of each endpoint in the given endpoint list.
#### Return value
##### Simple reply
On success, prints a humanized table of each endpoint URL, ID, version, database size, leadership status, raft term, and raft status. On failure, returns with a non-zero exit code.
##### JSON reply
On success, prints a line of JSON encoding each endpoint URL, ID, version, database size, leadership status, raft term, and raft status. On failure, returns with a non-zero exit code.
##### Protobuf reply
ENDPOINT STATUS does not support protobuf encoded output.
#### Examples
```bash
./etcdctl endpoint status
127.0.0.1:2379, 8211f1d0f64f3269, 3.0.0-beta.0+git, 25 kB, false, 2, 63
127.0.0.1:22379, 91bc3c398fb3c146, 3.0.0-beta.0+git, 25 kB, false, 2, 63
127.0.0.1:32379, fd422379fda50e48, 3.0.0-beta.0+git, 25 kB, true, 2, 63
```
```bash
./etcdctl -w json endpoint status
[{"Endpoint":"127.0.0.1:2379","Status":{"header":{"cluster_id":17237436991929493444,"member_id":9372538179322589801,"revision":2,"raft_term":2},"version":"2.3.0+git","dbSize":24576,"leader":18249187646912138824,"raftIndex":32623,"raftTerm":2}},{"Endpoint":"127.0.0.1:22379","Status":{"header":{"cluster_id":17237436991929493444,"member_id":10501334649042878790,"revision":2,"raft_term":2},"version":"2.3.0+git","dbSize":24576,"leader":18249187646912138824,"raftIndex":32623,"raftTerm":2}},{"Endpoint":"127.0.0.1:32379","Status":{"header":{"cluster_id":17237436991929493444,"member_id":18249187646912138824,"revision":2,"raft_term":2},"version":"2.3.0+git","dbSize":24576,"leader":18249187646912138824,"raftIndex":32623,"raftTerm":2}}]
```
```bash
./etcdctl -w table endpoint status
+-----------------+------------------+------------------+---------+-----------+-----------+------------+
| ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | RAFT TERM | RAFT INDEX |
+-----------------+------------------+------------------+---------+-----------+-----------+------------+
| 127.0.0.1:2379 | 8211f1d0f64f3269 | 3.0.0-beta.0+git | 25 kB | false | 2 | 52 |
| 127.0.0.1:22379 | 91bc3c398fb3c146 | 3.0.0-beta.0+git | 25 kB | false | 2 | 52 |
| 127.0.0.1:32379 | fd422379fda50e48 | 3.0.0-beta.0+git | 25 kB | true | 2 | 52 |
+-----------------+------------------+------------------+---------+-----------+-----------+------------+
```
### LOCK \<lockname\>
LOCK acquires a distributed named mutex with a given name. Once the lock is acquired, it will be held until etcdctl is terminated.
#### Return value
- Once the lock is acquired, the result for the GET on the unique lock holder key is displayed.
- LOCK returns a zero exit code only if it is terminated by a signal and can release the lock.
#### Example
```bash
./etcdctl lock mylock
mylock/1234534535445
```
#### Notes
The lease length of a lock defaults to 60 seconds. If LOCK is abnormally terminated, lock progress may be delayed
by up to 60 seconds.
### ELECT [options] \<election-name\> [proposal]
ELECT participates on a named election. A node announces its candidacy in the election by providing
a proposal value. If a node wishes to observe the election, ELECT listens for new leaders values.
Whenever a leader is elected, its proposal is given as output.
#### Options
- listen -- observe the election
#### Return value
- If a candidate, ELECT displays the GET on the leader key once the node is elected election.
- If observing, ELECT streams the result for a GET on the leader key for the current election and all future elections.
- ELECT returns a zero exit code only if it is terminated by a signal and can revoke its candidacy or leadership, if any.
#### Example
```bash
./etcdctl elect myelection foo
myelection/1456952310051373265
foo
```
#### Notes
The lease length of a leader defaults to 60 seconds. If a candidate is abnormally terminated, election
progress may be delayed by up to 60 seconds.
### COMPACTION \<revision\>
COMPACTION discards all etcd event history prior to a given revision. Since etcd uses a multiversion concurrency control
model, it preserves all key updates as event history. When the event history up to some revision is no longer needed,
all superseded keys may be compacted away to reclaim storage space in the etcd backend database.
#### Return value
- On success, prints the compacted revision and returns a zero exit code.
- On failure, prints an error message and returns with a non-zero exit code.
#### Example
```bash
./etcdctl compaction 1234
compacted revision 1234
```
### DEFRAG
DEFRAG defragments the backend database file for a set of given endpoints. When an etcd member reclaims storage space
from deleted and compacted keys, the space is kept in a free list and the database file remains the same size. By defragmenting
the database, the etcd member releases this free space back to the file system.
#### Return value
- If successfully defragmented an endpoint, prints a message indicating success for that endpoint.
- If failed defragmenting an endpoint, prints a message indicating failure for that endpoint.
- DEFRAG returns a zero exit code only if it succeeded defragmenting all given endpoints.
#### Example
```bash
./etcdctl --endpoints=localhost:2379,badendpoint:2379 defrag
Finished defragmenting etcd member[localhost:2379]
Failed to defragment etcd member[badendpoint:2379] (grpc: timed out trying to connect)
```
### MAKE-MIRROR [options] \<destination\>
[make-mirror][mirror] mirrors a key prefix in an etcd cluster to a destination etcd cluster.
#### Options
- dest-cacert -- TLS certificate authority file for destination cluster
- dest-cert -- TLS certificate file for destination cluster
- dest-key -- TLS key file for destination cluster
- prefix -- The key-value prefix to mirror
#### Return value
Simple reply
- The approximate total number of keys transferred to the destination cluster, updated every 30 seconds.
- Error string if mirroring failed. Exit code is non-zero.
#### Examples
```
./etcdctl make-mirror mirror.example.com:2379
10
18
```
[mirror]: ./doc/mirror_maker.md
### SNAPSHOT \<subcommand\>
SNAPSHOT provides commands to restore a snapshot of a running etcd server into a fresh cluster.
### SNAPSHOT SAVE \<filename\>
SNAPSHOT SAVE writes a point-in-time snapshot of the etcd backend database to a file.
#### Return value
- On success, the backend snapshot is written to the given file path.
- Error string if snapshotting failed. Exit code is non-zero.
#### Example
Save a snapshot to "snapshot.db":
```
./etcdctl snapshot save snapshot.db
```
### SNAPSHOT RESTORE [options] \<filename\>
SNAPSHOT RESTORE creates an etcd data directory for an etcd cluster member from a backend database snapshot and a new cluster configuration. Restoring the snapshot into each member for a new cluster configuration will initialize a new etcd cluster preloaded by the snapshot data.
#### Options
The snapshot restore options closely resemble to those used in the `etcd` command for defining a cluster.
- data-dir -- Path to the data directory. Uses \<name\>.etcd if none given.
- initial-cluster -- The initial cluster configuration for the restored etcd cluster.
- initial-cluster-token -- Initial cluster token for the restored etcd cluster.
- initial-advertise-peer-urls -- List of peer URLs for the member being restored.
- name -- Human-readable name for the etcd cluster member being restored.
#### Return value
- On success, a new etcd data directory is initialized.
- Error string if the data directory could not be completely initialized. Exit code is non-zero.
#### Example
Save a snapshot, restore into a new 3 node cluster, and start the cluster:
```
./etcdctl snapshot save snapshot.db
# restore members
bin/etcdctl snapshot restore snapshot.db --initial-cluster-token etcd-cluster-1 --initial-advertise-peer-urls http://127.0.0.1:12380 --name sshot1 --initial-cluster 'sshot1=http://127.0.0.1:12380,sshot2=http://127.0.0.1:22380,sshot3=http://127.0.0.1:32380'
bin/etcdctl snapshot restore snapshot.db --initial-cluster-token etcd-cluster-1 --initial-advertise-peer-urls http://127.0.0.1:22380 --name sshot2 --initial-cluster 'sshot1=http://127.0.0.1:12380,sshot2=http://127.0.0.1:22380,sshot3=http://127.0.0.1:32380'
bin/etcdctl snapshot restore snapshot.db --initial-cluster-token etcd-cluster-1 --initial-advertise-peer-urls http://127.0.0.1:32380 --name sshot3 --initial-cluster 'sshot1=http://127.0.0.1:12380,sshot2=http://127.0.0.1:22380,sshot3=http://127.0.0.1:32380'
# launch members
bin/etcd --name sshot1 --listen-client-urls http://127.0.0.1:2379 --advertise-client-urls http://127.0.0.1:2379 --listen-peer-urls http://127.0.0.1:12380 &
bin/etcd --name sshot2 --listen-client-urls http://127.0.0.1:22379 --advertise-client-urls http://127.0.0.1:22379 --listen-peer-urls http://127.0.0.1:22380 &
bin/etcd --name sshot3 --listen-client-urls http://127.0.0.1:32379 --advertise-client-urls http://127.0.0.1:32379 --listen-peer-urls http://127.0.0.1:32380 &
```
### SNAPSHOT STATUS \<filename\>
SNAPSHOT STATUS lists information about a given backend database snapshot file.
#### Return value
##### Simple Reply
On success, prints a humanized table of the database hash, revision, total keys, and size. On failure, return with a non-zero exit code.
##### JSON reply
On success, prints a line of JSON encoding the database hash, revision, total keys, and size. On failure, return with a non-zero exit code.
##### Protobuf reply
SNAPSHOT STATUS does not support protobuf encoded output.
#### Examples
```bash
./etcdctl snapshot status file.db
cf1550fb, 3, 3, 25 kB
```
```bash
./etcdctl -write-out=json snapshot status file.db
{"hash":3474280699,"revision":3,"totalKey":3,"totalSize":24576}
```
```bash
./etcdctl -write-out=table snapshot status file.db
+----------+----------+------------+------------+
| HASH | REVISION | TOTAL KEYS | TOTAL SIZE |
+----------+----------+------------+------------+
| cf1550fb | 3 | 3 | 25 kB |
+----------+----------+------------+------------+
```
### MIGRATE [options]
Migrate migrates keys in a v2 store to a mvcc store. Users should run migration command for all members in the cluster.
#### Options
- data-dir -- Path to the data directory
- wal-dir -- Path to the WAL directory
- transformer -- Path to the user-provided transformer program (default if not provided)
#### Return value
Simple reply
- Exit code is zero when migration is finished successfully.
- Error string if migration failed. Exit code is non-zero.
#### Default transformer
If user does not provide a transformer program, migrate command will use the default transformer. The default transformer transforms `storev2` formatted keys into `mvcc` formatted keys according to the following Go program:
```go
func transform(n *storev2.Node) *mvccpb.KeyValue {
if n.Dir {
return nil
}
kv := &mvccpb.KeyValue{
Key: []byte(n.Key),
Value: []byte(n.Value),
CreateRevision: int64(n.CreatedIndex),
ModRevision: int64(n.ModifiedIndex),
Version: 1,
}
return kv
}
```
#### User-provided transformer
Users can provide a customized 1:n transformer function that transforms a key from the v2 store to any number of keys in the mvcc store. The migration program writes JSON formatted [v2 store keys][v2key] to the transformer program's stdin, reads protobuf formatted [mvcc keys][v3key] back from the transformer program's stdout, and finishes migration by saving the transformed keys into the mvcc store.
The provided transformer should read until EOF and flush the stdout before exiting to ensure data integrity.
#### Example
```
./etcdctl --data-dir=/var/etcd --transformer=k8s-transformer
finished transforming keys
```
## Notes
- JSON encoding for keys and values uses base64 since they are byte strings.
[etcdrpc]: ../etcdserver/etcdserverpb/rpc.proto
[storagerpc]: ../mvcc/mvccpb/kv.proto
[member_list_rpc]: ../etcdserver/etcdserverpb/rpc.proto#L493-L497
## Compatibility Support
etcdctl is still in its early stage. We try out best to ensure fully compatible releases, however we might break compatibility to fix bugs or improve commands. If we intend to release a version of etcdctl with backward incompatibilities, we will provide notice prior to release and have instructions on how to upgrade.
### Input Compatibility
Input includes the command name, its flags, and its arguments. We ensure backward compatibility of the input of normal commands in non-interactive mode.
### Output Compatibility
Output includes output from etcdctl and its exit code. etcdctl provides `simple` output format by default.
We ensure compatibility for the `simple` output format of normal commands in non-interactive mode. Currently, we do not ensure
backward compatibility for `JSON` format and the format in non-interactive mode. Currently, we do not ensure backward compatibility of utility commands.
### TODO: compatibility with etcd server
[v2key]: ../store/node_extern.go#L28-L37
[v3key]: ../mvcc/mvccpb/kv.proto#L12-L29