--- title: Upgrade etcd from 3.4 to 3.5 --- In the general case, upgrading from etcd 3.4 to 3.5 can be a zero-downtime, rolling upgrade: - one by one, stop the etcd v3.4 processes and replace them with etcd v3.5 processes - after running all v3.5 processes, new features in v3.5 are available to the cluster Before [starting an upgrade](#upgrade-procedure), read through the rest of this guide to prepare. ### Upgrade checklists **NOTE:** When [migrating from v2 with no v3 data](https://github.com/etcd-io/etcd/issues/9480), etcd server v3.2+ panics when etcd restores from existing snapshots but no v3 `ETCD_DATA_DIR/member/snap/db` file. This happens when the server had migrated from v2 with no previous v3 data. This also prevents accidental v3 data loss (e.g. `db` file might have been moved). etcd requires that post v3 migration can only happen with v3 data. Do not upgrade to newer v3 versions until v3.0 server contains v3 data. Highlighted breaking changes in 3.5. #### Deprecated `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metrics v3.5 promoted `etcd_debugging_mvcc_db_total_size_in_bytes` Prometheus metrics to `etcd_mvcc_db_total_size_in_bytes`, in order to encourage etcd storage monitoring. And v3.5 completely deprcates `etcd_debugging_mvcc_db_total_size_in_bytes`. ```diff -etcd_debugging_mvcc_db_total_size_in_bytes +etcd_mvcc_db_total_size_in_bytes ``` Note that `etcd_debugging_*` namespace metrics have been marked as experimental. As we improve monitoring guide, we may promote more metrics. #### Deprecated `etcd_debugging_mvcc_put_total` Prometheus metrics v3.5 promoted `etcd_debugging_mvcc_put_total` Prometheus metrics to `etcd_mvcc_put_total`, in order to encourage etcd storage monitoring. And v3.5 completely deprcates `etcd_debugging_mvcc_put_total`. ```diff -etcd_debugging_mvcc_put_total +etcd_mvcc_put_total ``` Note that `etcd_debugging_*` namespace metrics have been marked as experimental. As we improve monitoring guide, we may promote more metrics. #### Deprecated `etcd_debugging_mvcc_delete_total` Prometheus metrics v3.5 promoted `etcd_debugging_mvcc_delete_total` Prometheus metrics to `etcd_mvcc_delete_total`, in order to encourage etcd storage monitoring. And v3.5 completely deprcates `etcd_debugging_mvcc_delete_total`. ```diff -etcd_debugging_mvcc_delete_total +etcd_mvcc_delete_total ``` Note that `etcd_debugging_*` namespace metrics have been marked as experimental. As we improve monitoring guide, we may promote more metrics. #### Deprecated `etcd_debugging_mvcc_txn_total` Prometheus metrics v3.5 promoted `etcd_debugging_mvcc_txn_total` Prometheus metrics to `etcd_mvcc_txn_total`, in order to encourage etcd storage monitoring. And v3.5 completely deprcates `etcd_debugging_mvcc_txn_total`. ```diff -etcd_debugging_mvcc_txn_total +etcd_mvcc_txn_total ``` Note that `etcd_debugging_*` namespace metrics have been marked as experimental. As we improve monitoring guide, we may promote more metrics. #### Deprecated `etcd_debugging_mvcc_range_total` Prometheus metrics v3.5 promoted `etcd_debugging_mvcc_range_total` Prometheus metrics to `etcd_mvcc_range_total`, in order to encourage etcd storage monitoring. And v3.5 completely deprcates `etcd_debugging_mvcc_range_total`. ```diff -etcd_debugging_mvcc_range_total +etcd_mvcc_range_total ``` Note that `etcd_debugging_*` namespace metrics have been marked as experimental. As we improve monitoring guide, we may promote more metrics. #### Deprecated `etcd --logger capnslog` v3.4 defaults to `--logger=zap` in order to support multiple log outputs and structured logging. **`etcd --logger=capnslog` has been deprecated in v3.5**, and now `--logger=zap` is the default. ```diff -etcd --logger=capnslog +etcd --logger=zap --log-outputs=stderr +# to write logs to stderr and a.log file at the same time +etcd --logger=zap --log-outputs=stderr,a.log ``` v3.4 adds `etcd --logger=zap` support for structured logging and multiple log outputs. Main motivation is to promote automated etcd monitoring, rather than looking back server logs when it starts breaking. Future development will make etcd log as few as possible, and make etcd easier to monitor with metrics and alerts. **`etcd --logger=capnslog` will be deprecated in v3.5.** #### Deprecated `etcd --log-output` v3.4 renamed [`etcd --log-output` to `--log-outputs`](https://github.com/etcd-io/etcd/pull/9624) to support multiple log outputs. **`etcd --log-output` has been deprecated in v3.5.** ```diff -etcd --log-output=stderr +etcd --log-outputs=stderr ``` #### Deprecated `etcd --debug` flag (now `--log-level=debug`) **`etcd --debug` flag has been deprecated.** ```diff -etcd --debug +etcd --log-level debug ``` #### Deprecated `etcd --log-package-levels` **`etcd --log-package-levels` flag for `capnslog` has been deprecated.** Now, **`etcd --logger=zap`** is the default. ```diff -etcd --log-package-levels 'etcdmain=CRITICAL,etcdserver=DEBUG' +etcd --logger=zap --log-outputs=stderr ``` #### Deprecated `[CLIENT-URL]/config/local/log` **`/config/local/log` endpoint is being deprecated in v3.5, as is `etcd --log-package-levels` flag.** ```diff -$ curl http://127.0.0.1:2379/config/local/log -XPUT -d '{"Level":"DEBUG"}' -# debug logging enabled ``` #### Changed gRPC gateway HTTP endpoints (deprecated `/v3beta`) Before ```bash curl -L http://localhost:2379/v3beta/kv/put \ -X POST -d '{"key": "Zm9v", "value": "YmFy"}' ``` After ```bash curl -L http://localhost:2379/v3/kv/put \ -X POST -d '{"key": "Zm9v", "value": "YmFy"}' ``` `/v3beta` has been removed in 3.5 release. ### Server upgrade checklists #### Upgrade requirements To upgrade an existing etcd deployment to 3.5, the running cluster must be 3.4 or greater. If it's before 3.4, please [upgrade to 3.4](upgrade_3_3.md) before upgrading to 3.5. Also, to ensure a smooth rolling upgrade, the running cluster must be healthy. Check the health of the cluster by using the `etcdctl endpoint health` command before proceeding. #### Preparation Before upgrading etcd, always test the services relying on etcd in a staging environment before deploying the upgrade to the production environment. Before beginning, [download the snapshot backup](../op-guide/maintenance.md#snapshot-backup). Should something go wrong with the upgrade, it is possible to use this backup to [downgrade](#downgrade) back to existing etcd version. Please note that the `snapshot` command only backs up the v3 data. For v2 data, see [backing up v2 datastore](../v2/admin_guide.md#backing-up-the-datastore). #### Mixed versions While upgrading, an etcd cluster supports mixed versions of etcd members, and operates with the protocol of the lowest common version. The cluster is only considered upgraded once all of its members are upgraded to version 3.5. Internally, etcd members negotiate with each other to determine the overall cluster version, which controls the reported version and the supported features. #### Limitations Note: If the cluster only has v3 data and no v2 data, it is not subject to this limitation. If the cluster is serving a v2 data set larger than 50MB, each newly upgraded member may take up to two minutes to catch up with the existing cluster. Check the size of a recent snapshot to estimate the total data size. In other words, it is safest to wait for 2 minutes between upgrading each member. For a much larger total data size, 100MB or more , this one-time process might take even more time. Administrators of very large etcd clusters of this magnitude can feel free to contact the [etcd team][etcd-contact] before upgrading, and we'll be happy to provide advice on the procedure. #### Downgrade If all members have been upgraded to v3.5, the cluster will be upgraded to v3.5, and downgrade from this completed state is **not possible**. If any single member is still v3.4, however, the cluster and its operations remains "v3.4", and it is possible from this mixed cluster state to return to using a v3.4 etcd binary on all members. Please [download the snapshot backup](../op-guide/maintenance.md#snapshot-backup) to make downgrading the cluster possible even after it has been completely upgraded. ### Upgrade procedure This example shows how to upgrade a 3-member v3.4 ectd cluster running on a local machine. #### Step 1: check upgrade requirements Is the cluster healthy and running v3.4.x? ```bash etcdctl --endpoints=localhost:2379,localhost:22379,localhost:32379 endpoint health <127.0.0.1:32380: use of closed network connection"} {"level":"info","ts":1526587299.1778402,"caller":"rafthttp/stream.go:459","msg":"stopped stream reader with remote peer","stream-reader-type":"stream MsgApp v2","local-member-id":"7339c4e5e833c029","remote-peer-id":"b548c2511513015"} {"level":"warn","ts":1526587299.1780295,"caller":"rafthttp/stream.go:436","msg":"lost TCP streaming connection with remote peer","stream-reader-type":"stream Message","local-member-id":"7339c4e5e833c029","remote-peer-id":"b548c2511513015","error":"read tcp 127.0.0.1:34634->127.0.0.1:32380: use of closed network connection"} {"level":"info","ts":1526587299.1780987,"caller":"rafthttp/stream.go:459","msg":"stopped stream reader with remote peer","stream-reader-type":"stream Message","local-member-id":"7339c4e5e833c029","remote-peer-id":"b548c2511513015"} {"level":"info","ts":1526587299.1781602,"caller":"rafthttp/peer.go:340","msg":"stopped remote peer","remote-peer-id":"b548c2511513015"} {"level":"info","ts":1526587299.1781986,"caller":"rafthttp/peer.go:333","msg":"stopping remote peer","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1802843,"caller":"rafthttp/stream.go:291","msg":"closed TCP streaming connection with remote peer","stream-writer-type":"stream MsgApp v2","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1803446,"caller":"rafthttp/stream.go:301","msg":"stopped TCP streaming connection with remote peer","stream-writer-type":"stream MsgApp v2","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1824749,"caller":"rafthttp/stream.go:291","msg":"closed TCP streaming connection with remote peer","stream-writer-type":"stream Message","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.18255,"caller":"rafthttp/stream.go:301","msg":"stopped TCP streaming connection with remote peer","stream-writer-type":"stream Message","remote-peer-id":"729934363faa4a24"} {"level":"info","ts":1526587299.18261,"caller":"rafthttp/pipeline.go:86","msg":"stopped HTTP pipelining with remote peer","local-member-id":"7339c4e5e833c029","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1827736,"caller":"rafthttp/stream.go:436","msg":"lost TCP streaming connection with remote peer","stream-reader-type":"stream MsgApp v2","local-member-id":"7339c4e5e833c029","remote-peer-id":"729934363faa4a24","error":"read tcp 127.0.0.1:51482->127.0.0.1:22380: use of closed network connection"} {"level":"info","ts":1526587299.182845,"caller":"rafthttp/stream.go:459","msg":"stopped stream reader with remote peer","stream-reader-type":"stream MsgApp v2","local-member-id":"7339c4e5e833c029","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1830168,"caller":"rafthttp/stream.go:436","msg":"lost TCP streaming connection with remote peer","stream-reader-type":"stream Message","local-member-id":"7339c4e5e833c029","remote-peer-id":"729934363faa4a24","error":"context canceled"} {"level":"warn","ts":1526587299.1831107,"caller":"rafthttp/peer_status.go:65","msg":"peer became inactive","peer-id":"729934363faa4a24","error":"failed to read 729934363faa4a24 on stream Message (context canceled)"} {"level":"info","ts":1526587299.1831737,"caller":"rafthttp/stream.go:459","msg":"stopped stream reader with remote peer","stream-reader-type":"stream Message","local-member-id":"7339c4e5e833c029","remote-peer-id":"729934363faa4a24"} {"level":"info","ts":1526587299.1832306,"caller":"rafthttp/peer.go:340","msg":"stopped remote peer","remote-peer-id":"729934363faa4a24"} {"level":"warn","ts":1526587299.1837125,"caller":"rafthttp/http.go:424","msg":"failed to find remote peer in cluster","local-member-id":"7339c4e5e833c029","remote-peer-id-stream-handler":"7339c4e5e833c029","remote-peer-id-from":"b548c2511513015","cluster-id":"7dee9ba76d59ed53"} {"level":"warn","ts":1526587299.1840093,"caller":"rafthttp/http.go:424","msg":"failed to find remote peer in cluster","local-member-id":"7339c4e5e833c029","remote-peer-id-stream-handler":"7339c4e5e833c029","remote-peer-id-from":"b548c2511513015","cluster-id":"7dee9ba76d59ed53"} {"level":"warn","ts":1526587299.1842315,"caller":"rafthttp/http.go:424","msg":"failed to find remote peer in cluster","local-member-id":"7339c4e5e833c029","remote-peer-id-stream-handler":"7339c4e5e833c029","remote-peer-id-from":"729934363faa4a24","cluster-id":"7dee9ba76d59ed53"} {"level":"warn","ts":1526587299.1844475,"caller":"rafthttp/http.go:424","msg":"failed to find remote peer in cluster","local-member-id":"7339c4e5e833c029","remote-peer-id-stream-handler":"7339c4e5e833c029","remote-peer-id-from":"729934363faa4a24","cluster-id":"7dee9ba76d59ed53"} {"level":"info","ts":1526587299.2056687,"caller":"embed/etcd.go:473","msg":"stopping serving peer traffic","address":"127.0.0.1:2380"} {"level":"info","ts":1526587299.205819,"caller":"embed/etcd.go:480","msg":"stopped serving peer traffic","address":"127.0.0.1:2380"} {"level":"info","ts":1526587299.2058413,"caller":"embed/etcd.go:289","msg":"closed etcd server","name":"s1","data-dir":"/tmp/etcd/s1","advertise-peer-urls":["http://localhost:2380"],"advertise-client-urls":["http://localhost:2379"]} ``` #### Step 4: restart the etcd server with same configuration Restart the etcd server with same configuration but with the new etcd binary. ```diff -etcd-old --name s1 \ +etcd-new --name s1 \ --data-dir /tmp/etcd/s1 \ --listen-client-urls http://localhost:2379 \ --advertise-client-urls http://localhost:2379 \ --listen-peer-urls http://localhost:2380 \ --initial-advertise-peer-urls http://localhost:2380 \ --initial-cluster s1=http://localhost:2380,s2=http://localhost:22380,s3=http://localhost:32380 \ --initial-cluster-token tkn \ --initial-cluster-state new ``` The new v3.5 etcd will publish its information to the cluster. At this point, cluster still operates as v3.4 protocol, which is the lowest common version. > `{"level":"info","ts":1526586617.1647713,"caller":"membership/cluster.go:485","msg":"set initial cluster version","cluster-id":"7dee9ba76d59ed53","local-member-id":"7339c4e5e833c029","cluster-version":"3.0"}` > `{"level":"info","ts":1526586617.1648536,"caller":"api/capability.go:76","msg":"enabled capabilities for version","cluster-version":"3.0"}` > `{"level":"info","ts":1526586617.1649303,"caller":"membership/cluster.go:473","msg":"updated cluster version","cluster-id":"7dee9ba76d59ed53","local-member-id":"7339c4e5e833c029","from":"3.0","from":"3.4"}` > `{"level":"info","ts":1526586617.1649797,"caller":"api/capability.go:76","msg":"enabled capabilities for version","cluster-version":"3.4"}` > `{"level":"info","ts":1526586617.2107732,"caller":"etcdserver/server.go:1770","msg":"published local member to cluster through raft","local-member-id":"7339c4e5e833c029","local-member-attributes":"{Name:s1 ClientURLs:[http://localhost:2379]}","request-path":"/0/members/7339c4e5e833c029/attributes","cluster-id":"7dee9ba76d59ed53","publish-timeout":7}` Verify that each member, and then the entire cluster, becomes healthy with the new v3.5 etcd binary: ```bash etcdctl endpoint health --endpoints=localhost:2379,localhost:22379,localhost:32379 < `{"level":"info","ts":1526586949.0920913,"caller":"api/capability.go:76","msg":"enabled capabilities for version","cluster-version":"3.5"}` > `{"level":"info","ts":1526586949.0921566,"caller":"etcdserver/server.go:2272","msg":"cluster version is updated","cluster-version":"3.5"}` Member 2: > `{"level":"info","ts":1526586949.092117,"caller":"membership/cluster.go:473","msg":"updated cluster version","cluster-id":"7dee9ba76d59ed53","local-member-id":"729934363faa4a24","from":"3.4","from":"3.5"}` > `{"level":"info","ts":1526586949.0923078,"caller":"api/capability.go:76","msg":"enabled capabilities for version","cluster-version":"3.5"}` Member 3: > `{"level":"info","ts":1526586949.0921423,"caller":"membership/cluster.go:473","msg":"updated cluster version","cluster-id":"7dee9ba76d59ed53","local-member-id":"b548c2511513015","from":"3.4","from":"3.5"}` > `{"level":"info","ts":1526586949.0922918,"caller":"api/capability.go:76","msg":"enabled capabilities for version","cluster-version":"3.5"}` ```bash endpoint health --endpoints=localhost:2379,localhost:22379,localhost:32379 <