Upgrade from Zulip 5 to Zulip 6 requires updating PostgreSQL version from 10 to 14.

Upgrade is supposed to be done by following these instructions. However, they are only possible, if Zulip installation is NOT dockerized. When installing Zulip with Docker, postgresql database runs in a separate container. Therefore, pg_upgradecluster command in Zulip container does not make sense and will fail, because the old database is not running locally.

This utility container based on tianon/docker-postgres-upgrade installs PostgreSQL versions 10 and 14 simultaneously. Additionally, the required pgroonga, hunspell-en-us, and Zulip stop words are installed. Container preparation and Zulip database upgrade could be performed, as explained below.

docker build -t zulip-postgres-upgrade .

The command below shall perform the database upgrade, with the following notes:

1. Older releases of Zulip are storing database in /opt/docker/zulip/postgresql - please make sure it is also the case for you, and use a different path if it's not
2. PGUSER is set to zulip - please make sure the TODO in your docker-compose.yml is also zulip, and change it accordingly if not

docker run --rm \
        -e PGUSER=zulip \
        -e POSTGRES_INITDB_ARGS="-U zulip" \
        -v /opt/docker/zulip/postgresql/data:/var/lib/postgresql/10/data \
        -v /opt/docker/zulip/postgresql14/data:/var/lib/postgresql/14/data \
        zulip-postgres-upgrade

Finalize the upgrade by switching swapping the databases:

cd /opt/docker/zulip
sudo mv postgresql postgresql10
sudo mv postgresql14 postgresql

Lastly, we must address the following issues:

1. Fix port 5432 failed: FATAL: no pg_hba.conf entry for host "192.168.144.5", user "zulip", database "zulip", no encryption error by adding the following config for the new database:

sudo sh -c 'echo "host all all all scram-sha-256" >>/opt/docker/zulip/postgresql/data/pg_hba.conf'

2. Fix connection to server at "database" (192.168.160.5), port 5432 failed: FATAL: password authentication failed for user "zulip":

docker-compose up -d
docker-compose stop zulip
docker-compose exec database bash
export DATABASE_USER=zulip
export PASSWORD=******
psql -U zulip -c "ALTER ROLE $DATABASE_USER PASSWORD '$PASSWORD';"
exit
docker-compose down

Now everything is ready for Zulip 6 deployment. We can rebase our settings to 6.2-0 branch and deploy Zulip:

git checkout 6.2-0
git am V6.2-Our-setup.patch
docker-compose up -d

1. Docker版PostgreSQL升级迁移（慎用Watchtower更新基础服务）
2. 10 to 11 role "postgres" does not exist

postgres@2419d8f284cc:~$ cat delete_old_cluster.sh
#!/bin/sh

rm -rf '/var/lib/postgresql/10/data'

postgres@2419d8f284cc:~$ cat update_extensions.sql
\connect zulip
ALTER EXTENSION "pgroonga" UPDATE;