6ae2d2cf51
The in-place pg_upgrade in the db entrypoint could crash-loop or fail on real clusters. This reworks it: - Idempotent, crash-safe: replace the fragile migration_in_progress marker with a state-driven guard on the old_data/new_data scratch dirs. An empty leftover means a run was interrupted before any data moved (data still intact at $PGDATA) so it is discarded and retried; a non-empty one means data may live only there, so it stops for manual recovery. Removes both the "mkdir: File exists" crash-loop and the silent fresh-initdb-over-live-data window. - Correct install user: pg_upgrade must run as the old cluster's bootstrap superuser (oid 10), and the new cluster must be initialised with that same user. It is not necessarily $POSTGRES_USER (clusters created with the default "postgres" superuser plus a separate app role are common). Detect it from the old cluster (briefly start it and read pg_roles where oid = 10) and use it for both the new cluster's initdb and the pg_upgrade -U argument. - Bump DB_ENTRYPOINT_VERSION to v3 so swarm reloads the (immutable) config. Verified on cctest: clean 13->17, interrupted-then-retried, and prod-like clusters whose install user is "postgres" with a separate "discourse" app role.
65 lines
2.8 KiB
Bash
65 lines
2.8 KiB
Bash
#!/bin/bash
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set -e
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OLDDATA=$PGDATA/old_data
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NEWDATA=$PGDATA/new_data
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echo "Running as $(id)"
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# The migration uses $OLDDATA/$NEWDATA as scratch and removes them when it
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# finishes; a leftover *empty* one means a run was interrupted before any data
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# moved (data still intact at $PGDATA) so we clear it and retry, while a
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# *non-empty* one means data may live only there, so we stop for manual recovery.
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for scratch in $OLDDATA $NEWDATA; do
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if [ -d "$scratch" ] && [ -n "$(ls -A "$scratch")" ]; then
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echo "FATAL: $scratch exists and is not empty - a previous migration did not"
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echo "complete and the data may only exist there. manual recovery necessary."
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exit 1
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fi
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done
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rm -rf $OLDDATA $NEWDATA
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if [ -f $PGDATA/PG_VERSION ]; then
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DATA_VERSION=$(cat $PGDATA/PG_VERSION)
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if [ -n "$DATA_VERSION" -a "$PG_MAJOR" != "$DATA_VERSION" ]; then
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echo "postgres data version $DATA_VERSION found, but need $PG_MAJOR. Starting migration"
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echo "Installing postgres $DATA_VERSION"
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sed -i "s/$/ $DATA_VERSION/" /etc/apt/sources.list.d/pgdg.list
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apt-get update && apt-get install -y --no-install-recommends \
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postgresql-$DATA_VERSION \
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&& rm -rf /var/lib/apt/lists/*
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# pg_upgrade must run as the old cluster's bootstrap superuser (the "install
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# user", oid 10), and the new cluster must be initialised with that same
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# user. It is not necessarily $POSTGRES_USER (e.g. clusters created with the
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# default "postgres" superuser and a separate app role), so read it from the
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# old cluster: briefly start it and ask, connecting as the app role we know.
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PGBIN=/usr/lib/postgresql/$DATA_VERSION/bin
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gosu postgres $PGBIN/pg_ctl -D $PGDATA -w \
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-o "-c listen_addresses= -c unix_socket_directories=/tmp" start
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INSTALL_USER=$(gosu postgres psql -h /tmp -U "$POSTGRES_USER" -d postgres -tAc \
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"select rolname from pg_roles where oid = 10")
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gosu postgres $PGBIN/pg_ctl -D $PGDATA -w stop
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echo "old cluster install user: $INSTALL_USER"
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echo "shuffling around"
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gosu postgres mkdir $OLDDATA $NEWDATA
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chmod 700 $OLDDATA $NEWDATA
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mv $PGDATA/* $OLDDATA/ || true
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echo "running initdb"
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# abuse entrypoint script for initdb by making server error out; initialise
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# the new cluster with the same superuser as the old one so pg_upgrade matches
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gosu postgres bash -c "export PGDATA=$NEWDATA POSTGRES_USER=$INSTALL_USER ; /usr/local/bin/docker-entrypoint.sh --invalid-arg || true"
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echo "running pg_upgrade"
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cd /tmp
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gosu postgres pg_upgrade --link -b /usr/lib/postgresql/$DATA_VERSION/bin -d $OLDDATA -D $NEWDATA -U $INSTALL_USER
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cp $OLDDATA/pg_hba.conf $NEWDATA/
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mv $NEWDATA/* $PGDATA
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rm -rf $OLDDATA
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rmdir $NEWDATA
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echo "migration complete"
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fi
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fi
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/usr/local/bin/docker-entrypoint.sh postgres
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