etcdctl is a command line client for etcd.

The v3 API is used by default on main branch. For the v2 API, make sure to set environment variable ETCDCTL_API=2. See also READMEv2.

If using released versions earlier than v3.4, set ETCDCTL_API=3 to use v3 API.

Global flags (e.g., dial-timeout, --cacert, --cert, --key) can be set with environment variables:

ETCDCTL_DIAL_TIMEOUT=3s
ETCDCTL_CACERT=/tmp/ca.pem
ETCDCTL_CERT=/tmp/cert.pem
ETCDCTL_KEY=/tmp/key.pem

Prefix flag strings with ETCDCTL_, convert all letters to upper-case, and replace dash(-) with underscore(_). Note that the environment variables with the prefix ETCDCTL_ can only be used with the etcdctl global flags. Also, the environment variable ETCDCTL_API is a special case variable for etcdctl internal use only.

PUT assigns the specified value with the specified key. If key already holds a value, it is overwritten.

RPC: Put

• lease -- lease ID (in hexadecimal) to attach to the key.

• prev-kv -- return the previous key-value pair before modification.

• ignore-value -- updates the key using its current value.

• ignore-lease -- updates the key using its current lease.

OK

./etcdctl put foo bar --lease=1234abcd
# OK
./etcdctl get foo
# foo
# bar
./etcdctl put foo --ignore-value # to detache lease
# OK

./etcdctl put foo bar --lease=1234abcd
# OK
./etcdctl put foo bar1 --ignore-lease # to use existing lease 1234abcd
# OK
./etcdctl get foo
# foo
# bar1

./etcdctl put foo bar1 --prev-kv
# OK
# foo
# bar
./etcdctl get foo
# foo
# bar1

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:

./etcdctl put <key> -- <value>
./etcdctl put -- <key> <value>

Providing <value> in a new line after using carriage return is not supported and etcdctl may hang in that case. For example, following case is not supported:

./etcdctl put <key>\r
<value>

A <value> can have multiple lines or spaces but it must be provided with a double-quote as demonstrated below:

./etcdctl put foo "bar1 2 3"

GET gets the key or a range of keys [key, range_end) if range_end is given.

RPC: Range

• 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

• print-value-only -- print only value when used with write-out=simple

• consistency -- Linearizable(l) or Serializable(s), defaults to Linearizable(l).

• from-key -- Get keys that are greater than or equal to the given key using byte compare

• keys-only -- Get only the keys

• max-create-revision -- restrict results to kvs with create revision lower or equal than the supplied revision

• min-create-revision -- restrict results to kvs with create revision greater or equal than the supplied revision

• max-mod-revision -- restrict results to kvs with modified revision lower or equal than the supplied revision

• min-mod-revision -- restrict results to kvs with modified revision greater or equal than the supplied revision

Prints the data in format below,

\<key\>\n\<value\>\n\<next_key\>\n\<next_value\>...

Note serializable requests are better for lower latency requirement, but stale data might be returned if serializable option (--consistency=s) is specified.

First, populate etcd with some keys:

./etcdctl put foo bar
# OK
./etcdctl put foo1 bar1
# OK
./etcdctl put foo2 bar2
# OK
./etcdctl put foo3 bar3
# OK

Get the key named foo:

./etcdctl get foo
# foo
# bar

Get all keys:

./etcdctl get --from-key ''
# foo
# bar
# foo1
# bar1
# foo2
# foo2
# foo3
# bar3

Get all keys with names greater than or equal to foo1:

./etcdctl get --from-key foo1
# foo1
# bar1
# foo2
# bar2
# foo3
# bar3

Get keys with names greater than or equal to foo1 and less than foo3:

./etcdctl get foo1 foo3
# foo1
# bar1
# foo2
# bar2

If any key or value contains non-printable characters or control characters, simple formatted output can be ambiguous due to new lines. To resolve this issue, set --hex to hex encode all strings.

Removes the specified key or range of keys [key, range_end) if range_end is given.

RPC: DeleteRange

• prefix -- delete keys by matching prefix

• prev-kv -- return deleted key-value pairs

• from-key -- delete keys that are greater than or equal to the given key using byte compare

Prints the number of keys that were removed in decimal if DEL succeeded.

./etcdctl put foo bar
# OK
./etcdctl del foo
# 1
./etcdctl get foo

./etcdctl put key val
# OK
./etcdctl del --prev-kv key
# 1
# key
# val
./etcdctl get key

./etcdctl put a 123
# OK
./etcdctl put b 456
# OK
./etcdctl put z 789
# OK
./etcdctl del --from-key a
# 3
./etcdctl get --from-key a

./etcdctl put zoo val
# OK
./etcdctl put zoo1 val1
# OK
./etcdctl put zoo2 val2
# OK
./etcdctl del --prefix zoo
# 3
./etcdctl get zoo2

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.

RPC: Txn

• hex -- print out keys and values as hex encoded strings.

• interactive -- input transaction with interactive prompting.

<Txn> ::= <CMP>* "\n" <THEN> "\n" <ELSE> "\n"
<CMP> ::= (<CMPCREATE>|<CMPMOD>|<CMPVAL>|<CMPVER>|<CMPLEASE>) "\n"
<CMPOP> ::= "<" | "=" | ">"
<CMPCREATE> := ("c"|"create")"("<KEY>")" <CMPOP> <REVISION>
<CMPMOD> ::= ("m"|"mod")"("<KEY>")" <CMPOP> <REVISION>
<CMPVAL> ::= ("val"|"value")"("<KEY>")" <CMPOP> <VALUE>
<CMPVER> ::= ("ver"|"version")"("<KEY>")" <CMPOP> <VERSION>
<CMPLEASE> ::= "lease("<KEY>")" <CMPOP> <LEASE>
<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]+"\""
<LEASE> ::= "\""[0-9]+\""

SUCCESS if etcd processed the transaction success list, FAILURE if etcd processed the transaction failure list. Prints the output for each command in the executed request list, each separated by a blank line.

txn in interactive mode:

./etcdctl txn -i
# compares:
mod("key1") > "0"

# success requests (get, put, delete):
put key1 "overwrote-key1"

# failure requests (get, put, delete):
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

When using multi-line values within a TXN command, newlines must be represented as \n. Literal newlines will cause parsing failures. This differs from other commands (such as PUT) where the shell will convert literal newlines for us. For example:

./etcdctl txn <<<'mod("key1") > "0"

put key1 "overwrote-key1"

put key1 "created-key1"
put key2 "this is\na multi-line\nvalue"

'

# FAILURE

# OK

# OK

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.

RPC: Compact

• physical -- 'true' to wait for compaction to physically remove all old revisions

Prints the compacted revision.

./etcdctl compaction 1234
# compacted revision 1234

Watch watches events stream on keys or prefixes, [key or prefix, range_end) if range_end is given. The watch command runs until it encounters an error or is terminated by the user. If range_end is given, it must be lexicographically greater than key or "\x00".

RPC: Watch

• 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.

• prev-kv -- get the previous key-value pair before the event happens.

• rev -- the revision to start watching. Specifying a revision is useful for observing past events.

Input is only accepted for interactive mode.

watch [options] <key or prefix>\n

<event>[\n<old_key>\n<old_value>]\n<key>\n<value>\n<event>\n<next_key>\n<next_value>\n...

./etcdctl watch foo
# PUT
# foo
# bar

ETCDCTL_WATCH_KEY=foo ./etcdctl watch
# PUT
# foo
# bar

Receive events and execute echo watch event received:

./etcdctl watch foo -- echo watch event received
# PUT
# foo
# bar
# watch event received

Watch response is set via ETCD_WATCH_* environmental variables:

./etcdctl watch foo -- sh -c "env | grep ETCD_WATCH_"

# PUT
# foo
# bar
# ETCD_WATCH_REVISION=11
# ETCD_WATCH_KEY="foo"
# ETCD_WATCH_EVENT_TYPE="PUT"
# ETCD_WATCH_VALUE="bar"

Watch with environmental variables and execute echo watch event received:

export ETCDCTL_WATCH_KEY=foo
./etcdctl watch -- echo watch event received
# PUT
# foo
# bar
# watch event received

export ETCDCTL_WATCH_KEY=foo
export ETCDCTL_WATCH_RANGE_END=foox
./etcdctl watch -- echo watch event received
# PUT
# fob
# bar
# watch event received

./etcdctl watch -i
watch foo
watch foo
# PUT
# foo
# bar
# PUT
# foo
# bar

Receive events and execute echo watch event received:

./etcdctl watch -i
watch foo -- echo watch event received
# PUT
# foo
# bar
# watch event received

Watch with environmental variables and execute echo watch event received:

export ETCDCTL_WATCH_KEY=foo
./etcdctl watch -i
watch -- echo watch event received
# PUT
# foo
# bar
# watch event received

export ETCDCTL_WATCH_KEY=foo
export ETCDCTL_WATCH_RANGE_END=foox
./etcdctl watch -i
watch -- echo watch event received
# PUT
# fob
# bar
# watch event received

LEASE provides commands for key lease management.

LEASE GRANT creates a fresh lease with a server-selected time-to-live in seconds greater than or equal to the requested TTL value.

RPC: LeaseGrant

Prints a message with the granted lease ID.

./etcdctl lease grant 60
# lease 32695410dcc0ca06 granted with TTL(60s)

LEASE REVOKE destroys a given lease, deleting all attached keys.

RPC: LeaseRevoke

Prints a message indicating the lease is revoked.

./etcdctl lease revoke 32695410dcc0ca06
# lease 32695410dcc0ca06 revoked

LEASE TIMETOLIVE retrieves the lease information with the given lease ID.

RPC: LeaseTimeToLive

• keys -- Get keys attached to this lease

Prints lease information.

./etcdctl lease grant 500
# lease 2d8257079fa1bc0c granted with TTL(500s)

./etcdctl put foo1 bar --lease=2d8257079fa1bc0c
# OK

./etcdctl put foo2 bar --lease=2d8257079fa1bc0c
# OK

./etcdctl lease timetolive 2d8257079fa1bc0c
# lease 2d8257079fa1bc0c granted with TTL(500s), remaining(481s)

./etcdctl lease timetolive 2d8257079fa1bc0c --keys
# lease 2d8257079fa1bc0c granted with TTL(500s), remaining(472s), attached keys([foo2 foo1])

./etcdctl lease timetolive 2d8257079fa1bc0c --write-out=json
# {"cluster_id":17186838941855831277,"member_id":4845372305070271874,"revision":3,"raft_term":2,"id":3279279168933706764,"ttl":465,"granted-ttl":500,"keys":null}

./etcdctl lease timetolive 2d8257079fa1bc0c --write-out=json --keys
# {"cluster_id":17186838941855831277,"member_id":4845372305070271874,"revision":3,"raft_term":2,"id":3279279168933706764,"ttl":459,"granted-ttl":500,"keys":["Zm9vMQ==","Zm9vMg=="]}

./etcdctl lease timetolive 2d8257079fa1bc0c
# lease 2d8257079fa1bc0c already expired

LEASE LIST lists all active leases.

RPC: LeaseLeases

Prints a message with a list of active leases.

./etcdctl lease grant 60
# lease 32695410dcc0ca06 granted with TTL(60s)

./etcdctl lease list
32695410dcc0ca06

LEASE KEEP-ALIVE periodically refreshes a lease so it does not expire.

RPC: LeaseKeepAlive

Prints a message for every keep alive sent or prints a message indicating the lease is gone.

./etcdctl lease keep-alive 32695410dcc0ca0
# lease 32695410dcc0ca0 keepalived with TTL(100)
# lease 32695410dcc0ca0 keepalived with TTL(100)
# lease 32695410dcc0ca0 keepalived with TTL(100)
...

MEMBER provides commands for managing etcd cluster membership.

MEMBER ADD introduces a new member into the etcd cluster as a new peer.

RPC: MemberAdd

• peer-urls -- comma separated list of URLs to associate with the new member.

Prints the member ID of the new member and the cluster ID.

./etcdctl member add newMember --peer-urls=https://127.0.0.1:12345

Member ced000fda4d05edf added to cluster 8c4281cc65c7b112

ETCD_NAME="newMember"
ETCD_INITIAL_CLUSTER="newMember=https://127.0.0.1:12345,default=http://10.0.0.30:2380"
ETCD_INITIAL_CLUSTER_STATE="existing"

MEMBER UPDATE sets the peer URLs for an existing member in the etcd cluster.

RPC: MemberUpdate

• peer-urls -- comma separated list of URLs to associate with the updated member.

Prints the member ID of the updated member and the cluster ID.

./etcdctl member update 2be1eb8f84b7f63e --peer-urls=https://127.0.0.1:11112
# Member 2be1eb8f84b7f63e updated in cluster ef37ad9dc622a7c4

MEMBER REMOVE removes a member of an etcd cluster from participating in cluster consensus.

RPC: MemberRemove

Prints the member ID of the removed member and the cluster ID.

./etcdctl member remove 2be1eb8f84b7f63e
# Member 2be1eb8f84b7f63e removed from cluster ef37ad9dc622a7c4

MEMBER LIST prints the member details for all members associated with an etcd cluster.

RPC: MemberList

• consistency -- Linearizable(l) or Serializable(s), defaults to Linearizable(l).

Prints a humanized table of the member IDs, statuses, names, peer addresses, and client addresses.

Note serializable requests are better for lower latency requirement, but stale member list might be returned if serializable option (--consistency=s) is specified. In some situations users may want to use serializable requests. For example, when adding a new member to a one-node cluster, it's reasonable and safe to use serializable request before the new added member gets started.

./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

./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"]}]}

./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 |
+------------------+---------+--------+------------------------+------------------------+

ENDPOINT provides commands for querying individual endpoints.

• cluster -- fetch and use all endpoints from the etcd cluster member list

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.

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.

Check the default endpoint's health:

./etcdctl endpoint health
# 127.0.0.1:2379 is healthy: successfully committed proposal: took = 2.095242ms

Check all endpoints for the cluster associated with the default endpoint:

./etcdctl endpoint --cluster health
# http://127.0.0.1:2379 is healthy: successfully committed proposal: took = 1.060091ms
# http://127.0.0.1:22379 is healthy: successfully committed proposal: took = 903.138µs
# http://127.0.0.1:32379 is healthy: successfully committed proposal: took = 1.113848ms

ENDPOINT STATUS queries the status of each endpoint in the given endpoint list.

Prints a humanized table of each endpoint URL, ID, version, database size, leadership status, raft term, and raft status.

Prints a line of JSON encoding each endpoint URL, ID, version, database size, leadership status, raft term, and raft status.

Get the status for the default endpoint:

./etcdctl endpoint status
# 127.0.0.1:2379, 8211f1d0f64f3269, 3.0.0, 25 kB, false, 2, 63

Get the status for the default endpoint as JSON:

./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":"3.0.0","dbSize":24576,"leader":18249187646912138824,"raftIndex":32623,"raftTerm":2}}]

Get the status for all endpoints in the cluster associated with the default endpoint:

./etcdctl -w table endpoint --cluster status
+------------------------+------------------+---------------+-----------------+---------+----------------+-----------+------------+-----------+------------+--------------------+--------+
|        ENDPOINT        |        ID        |    VERSION    | STORAGE VERSION | DB SIZE | DB SIZE IN USE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS |
+------------------------+------------------+---------------+-----------------+---------+----------------+-----------+------------+-----------+------------+--------------------+--------+
|  http://127.0.0.1:2379 | 8211f1d0f64f3269 | 3.6.0-alpha.0 |           3.6.0 |   25 kB |          25 kB |     false |      false |         2 |          8 |                  8 |        |
| http://127.0.0.1:22379 | 91bc3c398fb3c146 | 3.6.0-alpha.0 |           3.6.0 |   25 kB |          25 kB |      true |      false |         2 |          8 |                  8 |        |
| http://127.0.0.1:32379 | fd422379fda50e48 | 3.6.0-alpha.0 |           3.6.0 |   25 kB |          25 kB |     false |      false |         2 |          8 |                  8 |        |
+------------------------+------------------+---------------+-----------------+---------+----------------+-----------+------------+-----------+------------+--------------------+--------+

ENDPOINT HASHKV fetches the hash of the key-value store of an endpoint.

Prints a humanized table of each endpoint URL and KV history hash.

Prints a line of JSON encoding each endpoint URL and KV history hash.

Get the hash for the default endpoint:

./etcdctl endpoint hashkv --cluster
http://127.0.0.1:2379, 2064120424, 13
http://127.0.0.1:22379, 2064120424, 13
http://127.0.0.1:32379, 2064120424, 13

Get the status for the default endpoint as JSON:

./etcdctl endpoint hash --cluster -w json | jq
[
  {
    "Endpoint": "http://127.0.0.1:2379",
    "HashKV": {
      "header": {
        "cluster_id": 17237436991929494000,
        "member_id": 9372538179322590000,
        "revision": 13,
        "raft_term": 2
      },
      "hash": 2064120424,
      "compact_revision": -1,
      "hash_revision": 13
    }
  },
  {
    "Endpoint": "http://127.0.0.1:22379",
    "HashKV": {
      "header": {
        "cluster_id": 17237436991929494000,
        "member_id": 10501334649042878000,
        "revision": 13,
        "raft_term": 2
      },
      "hash": 2064120424,
      "compact_revision": -1,
      "hash_revision": 13
    }
  },
  {
    "Endpoint": "http://127.0.0.1:32379",
    "HashKV": {
      "header": {
        "cluster_id": 17237436991929494000,
        "member_id": 18249187646912140000,
        "revision": 13,
        "raft_term": 2
      },
      "hash": 2064120424,
      "compact_revision": -1,
      "hash_revision": 13
    }
  }
]

Get the status for all endpoints in the cluster associated with the default endpoint:

$ ./etcdctl endpoint hash --cluster -w table
+------------------------+-----------+---------------+
|        ENDPOINT        |   HASH    | HASH REVISION |
+------------------------+-----------+---------------+
|  http://127.0.0.1:2379 | 784522900 |            16 |
| http://127.0.0.1:22379 | 784522900 |            16 |
| http://127.0.0.1:32379 | 784522900 |            16 |
+------------------------+-----------+---------------+

Provides alarm related commands

alarm disarm Disarms all alarms

RPC: Alarm

alarm:<alarm type> if alarm is present and disarmed.

./etcdctl alarm disarm

If NOSPACE alarm is present:

./etcdctl alarm disarm
# alarm:NOSPACE

alarm list lists all alarms.

RPC: Alarm

alarm:<alarm type> if alarm is present, empty string if no alarms present.

./etcdctl alarm list

If NOSPACE alarm is present:

./etcdctl alarm list
# alarm:NOSPACE

DEFRAG defragments the backend database file for a set of given endpoints while etcd is running. 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.

Note: to defragment offline (--data-dir flag), use: etcutl defrag instead

Note that defragmentation to a live member blocks the system from reading and writing data while rebuilding its states.

Note that defragmentation request does not get replicated over cluster. That is, the request is only applied to the local node. Specify all members in --endpoints flag or --cluster flag to automatically find all cluster members.

For each endpoints, prints a message indicating whether the endpoint was successfully defragmented.

./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)

Run defragment operations for all endpoints in the cluster associated with the default endpoint:

./etcdctl defrag --cluster
Finished defragmenting etcd member[http://127.0.0.1:2379]
Finished defragmenting etcd member[http://127.0.0.1:22379]
Finished defragmenting etcd member[http://127.0.0.1:32379]

DEFRAG returns a zero exit code only if it succeeded defragmenting all given endpoints.

SNAPSHOT provides commands to restore a snapshot of a running etcd server into a fresh cluster.

SNAPSHOT SAVE writes a point-in-time snapshot of the etcd backend database to a file.

The backend snapshot is written to the given file path.

Save a snapshot to "snapshot.db":

./etcdctl snapshot save snapshot.db

Removed in v3.6. Use etcdutl snapshot restore instead.

Removed in v3.6. Use etcdutl snapshot status instead.

MOVE-LEADER transfers leadership from the leader to another member in the cluster.

# to choose transferee
transferee_id=$(./etcdctl \
  --endpoints localhost:2379,localhost:22379,localhost:32379 \
  endpoint status | grep -m 1 "false" | awk -F', ' '{print $2}')
echo ${transferee_id}
# c89feb932daef420

# endpoints should include leader node
./etcdctl --endpoints ${transferee_ep} move-leader ${transferee_id}
# Error:  no leader endpoint given at [localhost:22379 localhost:32379]

# request to leader with target node ID
./etcdctl --endpoints ${leader_ep} move-leader ${transferee_id}
# Leadership transferred from 45ddc0e800e20b93 to c89feb932daef420

NOTICE: Downgrades is an experimental feature in v3.6 and is not recommended for production clusters.

Downgrade provides commands to downgrade cluster. Normally etcd members cannot be downgraded due to cluster version mechanism.

After initial bootstrap, cluster members agree on the cluster version. Every 5 seconds, leader checks versions of all members and picks lowers minor version. New members will refuse joining cluster with cluster version newer than theirs, thus preventing cluster from downgrading. Downgrade commands allow cluster administrator to force cluster version to be lowered to previous minor version, thus allowing to downgrade the cluster.

Downgrade should be executed in stages:

1. Verify that cluster is ready to be downgraded by running etcdctl downgrade validate <TARGET_VERSION>
2. Start the downgrade process by running etcdctl downgrade enable <TARGET_VERSION>
3. For each cluster member:
   1. Ensure that member is ready for downgrade by confirming that it wrote The server is ready to downgrade log.
   2. Replace member binary with one with older version.
   3. Confirm that member has correctly started and joined the cluster.
4. Ensure that downgrade process has succeeded by checking leader log for the cluster has been downgraded

Downgrade can be canceled by running etcdctl downgrade cancel command.

In case of downgrade being canceled, cluster version will return to its normal behavior (pick the lowest member minor version). If no members were downgraded, cluster version will return to original value. If at least one member was downgraded, cluster version will stay at the <TARGET_VALUE> until downgraded members are upgraded back.

DOWNGRADE VALIDATE validate downgrade capability before starting downgrade.

./etcdctl downgrade validate 3.5
Downgrade validate success, cluster version 3.6

./etcdctl downgrade validate 3.4
Error: etcdserver: invalid downgrade target version

DOWNGRADE ENABLE starts a downgrade action to cluster.

./etcdctl downgrade enable 3.5
Downgrade enable success, cluster version 3.6

DOWNGRADE CANCEL cancels the ongoing downgrade action to cluster.

./etcdctl downgrade cancel
Downgrade cancel success, cluster version 3.5

LOCK acquires a distributed mutex with a given name. Once the lock is acquired, it will be held until etcdctl is terminated.

• ttl - time out in seconds of lock session.

Once the lock is acquired but no command is given, the result for the GET on the unique lock holder key is displayed.

If a command is given, it will be executed with environment variables ETCD_LOCK_KEY and ETCD_LOCK_REV set to the lock's holder key and revision.

Acquire lock with standard output display:

./etcdctl lock mylock
# mylock/1234534535445

Acquire lock and execute echo lock acquired:

./etcdctl lock mylock echo lock acquired
# lock acquired

Acquire lock and execute etcdctl put command

./etcdctl lock mylock ./etcdctl put foo bar
# OK

LOCK returns a zero exit code only if it is terminated by a signal and releases the lock.

If LOCK is abnormally terminated or fails to contact the cluster to release the lock, the lock will remain held until the lease expires. Progress may be delayed by up to the default lease length of 60 seconds.

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.

• listen -- observe the election.

• 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.

./etcdctl elect myelection foo
# myelection/1456952310051373265
# foo

ELECT returns a zero exit code only if it is terminated by a signal and can revoke its candidacy or leadership, if any.

If a candidate is abnormally terminated, election progress may be delayed by up to the default lease length of 60 seconds.

auth enable activates authentication on an etcd cluster and auth disable deactivates. When authentication is enabled, etcd checks all requests for appropriate authorization.

RPC: AuthEnable/AuthDisable

Authentication Enabled.

./etcdctl user add root
# Password of root:#type password for root
# Type password of root again for confirmation:#re-type password for root
# User root created
./etcdctl user grant-role root root
# Role root is granted to user root
./etcdctl user get root
# User: root
# Roles: root
./etcdctl role add root
# Role root created
./etcdctl role get root
# Role root
# KV Read:
# KV Write:
./etcdctl auth enable
# Authentication Enabled

ROLE is used to specify different roles which can be assigned to etcd user(s).

role add creates a role.

RPC: RoleAdd

Role <role name> created.

./etcdctl --user=root:123 role add myrole
# Role myrole created

role get lists detailed role information.

RPC: RoleGet

Detailed role information.

./etcdctl --user=root:123 role get myrole
# Role myrole
# KV Read:
# foo
# KV Write:
# foo

role delete deletes a role.

RPC: RoleDelete

Role <role name> deleted.

./etcdctl --user=root:123 role delete myrole
# Role myrole deleted

role list lists all roles in etcd.

RPC: RoleList

A role per line.

./etcdctl --user=root:123 role list
# roleA
# roleB
# myrole

role grant-permission grants a key to a role.

RPC: RoleGrantPermission

• from-key -- grant a permission of keys that are greater than or equal to the given key using byte compare

• prefix -- grant a prefix permission

Role <role name> updated.

Grant read and write permission on the key foo to role myrole:

./etcdctl --user=root:123 role grant-permission myrole readwrite foo
# Role myrole updated

Grant read permission on the wildcard key pattern foo/* to role myrole:

./etcdctl --user=root:123 role grant-permission --prefix myrole readwrite foo/
# Role myrole updated

role revoke-permission revokes a key from a role.

RPC: RoleRevokePermission

• from-key -- revoke a permission of keys that are greater than or equal to the given key using byte compare

• prefix -- revoke a prefix permission

Permission of key <key> is revoked from role <role name> for single key. Permission of range [<key>, <endkey>) is revoked from role <role name> for a key range. Exit code is zero.

./etcdctl --user=root:123 role revoke-permission myrole foo
# Permission of key foo is revoked from role myrole

USER provides commands for managing users of etcd.

user add creates a user.

RPC: UserAdd

• interactive -- Read password from stdin instead of interactive terminal

User <user name> created.

./etcdctl --user=root:123 user add myuser
# Password of myuser: #type password for my user
# Type password of myuser again for confirmation:#re-type password for my user
# User myuser created

user get lists detailed user information.

RPC: UserGet

• detail -- Show permissions of roles granted to the user

Detailed user information.

./etcdctl --user=root:123 user get myuser
# User: myuser
# Roles:

user delete deletes a user.

RPC: UserDelete

User <user name> deleted.

./etcdctl --user=root:123 user delete myuser
# User myuser deleted

user list lists detailed user information.

RPC: UserList

• List of users, one per line.

./etcdctl --user=root:123 user list
# user1
# user2
# myuser

user passwd changes a user's password.

RPC: UserChangePassword

• interactive -- if true, read password in interactive terminal

Password updated.

./etcdctl --user=root:123 user passwd myuser
# Password of myuser: #type new password for my user
# Type password of myuser again for confirmation: #re-type the new password for my user
# Password updated

user grant-role grants a role to a user

RPC: UserGrantRole

Role <role name> is granted to user <user name>.

./etcdctl --user=root:123 user grant-role userA roleA
# Role roleA is granted to user userA

user revoke-role revokes a role from a user

RPC: UserRevokeRole

Role <role name> is revoked from user <user name>.

./etcdctl --user=root:123 user revoke-role userA roleA
# Role roleA is revoked from user userA

make-mirror mirrors a key prefix in an etcd cluster to a destination etcd cluster.

• 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

• dest-prefix -- The destination prefix to mirror a prefix to a different prefix in the destination cluster

• no-dest-prefix -- Mirror key-values to the root of the destination cluster

• dest-insecure-transport -- Disable transport security for client connections

• max-txn-ops -- Maximum number of operations permitted in a transaction during syncing updates

The approximate total number of keys transferred to the destination cluster, updated every 30 seconds.

./etcdctl make-mirror mirror.example.com:2379
# 10
# 18

Prints the version of etcdctl.

Prints etcd version and API version.

./etcdctl version
# etcdctl version: 3.1.0-alpha.0+git
# API version: 3.1

CHECK provides commands for checking properties of the etcd cluster.

CHECK PERF checks the performance of the etcd cluster for 60 seconds. Running the check perf often can create a large keyspace history which can be auto compacted and defragmented using the --auto-compact and --auto-defrag options as described below.

Notice that different workload models use different configurations in terms of number of clients and throughput. Here is the configuration for each load:

The test checks for the following conditions:

• The throughput should be at least 90% of the issued request
• All the requests should be done in less than 500 ms
• The standard deviation of the requests should be less than 100 ms

Hence, a workload model may work while another one might fail.

RPC: CheckPerf

• load -- the performance check's workload model. Accepted workloads: s(small), m(medium), l(large), xl(xLarge)

• prefix -- the prefix for writing the performance check's keys.

• auto-compact -- if true, compact storage with last revision after test is finished.

• auto-defrag -- if true, defragment storage after test is finished.

Prints the result of performance check on different criteria like throughput. Also prints an overall status of the check as pass or fail.

Shows examples of both, pass and fail, status. The failure is due to the fact that a large workload was tried on a single node etcd cluster running on a laptop environment created for development and testing purpose.

./etcdctl check perf --load="s"
# 60 / 60 Booooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo! 100.00%1m0s
# PASS: Throughput is 150 writes/s
# PASS: Slowest request took 0.087509s
# PASS: Stddev is 0.011084s
# PASS
./etcdctl check perf --load="l"
# 60 / 60 Booooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo! 100.00%1m0s
# FAIL: Throughput too low: 6808 writes/s
# PASS: Slowest request took 0.228191s
# PASS: Stddev is 0.033547s
# FAIL

CHECK DATASCALE checks the memory usage of holding data for different workloads on a given server endpoint. Running the check datascale often can create a large keyspace history which can be auto compacted and defragmented using the --auto-compact and --auto-defrag options as described below.

RPC: CheckDatascale

• load -- the datascale check's workload model. Accepted workloads: s(small), m(medium), l(large), xl(xLarge)

• prefix -- the prefix for writing the datascale check's keys.

• auto-compact -- if true, compact storage with last revision after test is finished.

• auto-defrag -- if true, defragment storage after test is finished.

Prints the system memory usage for a given workload. Also prints status of compact and defragment if related options are passed.

./etcdctl check datascale --load="s" --auto-compact=true --auto-defrag=true
# Start data scale check for work load [10000 key-value pairs, 1024 bytes per key-value, 50 concurrent clients].
# Compacting with revision 18346204
# Compacted with revision 18346204
# Defragmenting "127.0.0.1:2379"
# Defragmented "127.0.0.1:2379"
# PASS: Approximate system memory used : 64.30 MB.

For all commands, a successful execution return a zero exit code. All failures will return non-zero exit codes.

All commands accept an output format by setting -w or --write-out. All commands default to the "simple" output format, which is meant to be human-readable. The simple format is listed in each command's Output description since it is customized for each command. If a command has a corresponding RPC, it will respect all output formats.

If a command fails, returning a non-zero exit code, an error string will be written to standard error regardless of output format.

A format meant to be easy to parse and human-readable. Specific to each command.

The JSON encoding of the command's RPC response. Since etcd's RPCs use byte strings, the JSON output will encode keys and values in base64.

Some commands without an RPC also support JSON; see the command's Output description.

The protobuf encoding of the command's RPC response. If an RPC is streaming, the stream messages will be concetenated. If an RPC is not given for a command, the protobuf output is not defined.

An output format similar to JSON but meant to parse with coreutils. For an integer field named Field, it writes a line in the format "Field" : %d where %d is go's integer formatting. For byte array fields, it writes "Field" : %q where %q is go's quoted string formatting (e.g., []byte{'a', '\n'} is written as "a\n").

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 includes the command name, its flags, and its arguments. We ensure backward compatibility of the input of normal commands in non-interactive mode.

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.