[DPE-2897] Cross-region async replication #447
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Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
marceloneppel
requested review from
delgod,
taurus-forever,
dragomirp and
lucasgameiroborges
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
…ation Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
taurus-forever
approved these changes
Apr 29, 2024
| filename = f"{POSTGRESQL_DATA_PATH}-{str(datetime.now()).replace(' ', '-').replace(':', '-')}.tar.gz" | ||
| self.container.exec( | ||
| f"tar -zcf {filename} {POSTGRESQL_DATA_PATH}".split() | ||
| ).wait_output() |
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Please create followup tickets:
- pack archive in background (otherwise promotion to Standby will take a LOT of time if local DB is huge)
- warn users about available backups to clean (free disk space topic), goss is a good match here
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…ation Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
dragomirp
reviewed
May 2, 2024
poetry.lock
Outdated
| @@ -1645,7 +1645,6 @@ files = [ | |||
| {file = "PyYAML-6.0.1-cp311-cp311-win_amd64.whl", hash = "sha256:bf07ee2fef7014951eeb99f56f39c9bb4af143d8aa3c21b1677805985307da34"}, | |||
| {file = "PyYAML-6.0.1-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:855fb52b0dc35af121542a76b9a84f8d1cd886ea97c84703eaa6d88e37a2ad28"}, | |||
| {file = "PyYAML-6.0.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:40df9b996c2b73138957fe23a16a4f0ba614f4c0efce1e9406a184b6d07fa3a9"}, | |||
| {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a08c6f0fe150303c1c6b71ebcd7213c2858041a7e01975da3a99aed1e7a378ef"}, | |||
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I think you can avoid those flyby changes by running poetry cache clear PyPI --all and then poetry lock --no-update
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Thanks. It did the trick.
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
dragomirp
approved these changes
May 2, 2024
BON4
pushed a commit
to BON4/postgresql-k8s-operator
that referenced
this pull request
May 20, 2024
* Add async replication implementation Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Backup standby pgdata folder Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Improve comments and logs Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Remove unused constant Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Remove warning log call and add optional type hint Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Revert poetry.lock Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> * Revert poetry.lock Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com> --------- Signed-off-by: Marcelo Henrique Neppel <marcelo.neppel@canonical.com>
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Issue
It's not possible to replicate data between regions.
Solution
Implement cross-region async replication. This PR is a rebranded and more stable version of #368.
With this PR, it's no longer necessary to remove the relation and relate again when a switchover is needed.
Also, the names of the relations can easily be changed to others, like
cluster-oneandcluster-two, for example, to avoid confusing users.Important changes:
src/relations/async_replication.pycontains the logic to make one cluster the primary and the other the standby. To make the standby cluster follow the primary cluster, the candidate for the standby cluster needs to be restarted._on_async_relation_changed, which takes care of restarting the standby cluster units databases in order to make them replicate data from the primary cluster.The
127.0.0.6/32address added to the Patroni configuration file is needed to allow Envoy to make different clusters communicate when using Istio.Passwords update will be implemented in another PR, as this one is already huge.
If the standby cluster has its relation removed, it goes to a
read-only modeand can be promoted later to a normal cluster through thepromote-clusteraction.How to deploy: https://discourse.charmhub.io/t/charmed-postgresql-k8s-deploy-async-replication/13895
How to trigger a switchover: https://discourse.charmhub.io/t/charmed-postgresql-k8s-deploy-async-replication/13895
Additional instructions:
Integration tests: #448