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Ruben Hensen
175769d36c
dqlite supports VACUUM from v1.18.2, which microk8s 1.34 ships, but the dqlite shell wraps every statement in a transaction and SQLite refuses to VACUUM inside one. dqlite-vacuum sends it through the go-dqlite driver instead and otherwise just prints page statistics. dqlite-vacuum.sh makes the backups first. Rehearsed on opti1 on a throwaway node in /dev/shm: 657 MB to 41 MB in 0.6s, with concurrent writes unaffected and the data intact after restarts.
41 lines
1.9 KiB
Bash
41 lines
1.9 KiB
Bash
#!/bin/bash
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# VACUUM the k8s-dqlite database, see "Shrink the database" in
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# docs/upgrade-k8s-1.33.md. Copy this script and the tool next to it to the
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# home directory on opti1; build the tool with
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# CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -o dqlite-vacuum .
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#
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# Rehearsed on a throwaway node with the binaries of microk8s 1.34: 657 MB to
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# 41 MB in 0.6s, writes next to it kept working, and the data was intact
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# after a restart and after the first snapshot.
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#
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# To go back to the state before the VACUUM:
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# sudo snap stop microk8s.daemon-k8s-dqlite
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# cd /var/snap/microk8s/current/var/kubernetes
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# sudo mv backend backend.vacuumed && sudo tar -xpf /root/backend-pre-vacuum-<stamp>.tar
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# sudo snap start microk8s.daemon-k8s-dqlite
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set -euo pipefail
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stamp=$(date +%Y%m%d-%H%M)
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kube=/var/snap/microk8s/current/var/kubernetes
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shell="/snap/microk8s/current/bin/dqlite -s 127.0.0.1:19001 -c $kube/backend/cluster.crt -k $kube/backend/cluster.key --timeout 60000 k8s"
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echo "== $(date) start"
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echo "== datastore backup to /root/dqlite-pre-vacuum-$stamp.tar.gz"
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sudo microk8s dbctl backup -o /root/dqlite-pre-vacuum-$stamp
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echo "== offline copy of the backend (API down ~1 min, pods keep running)"
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sudo snap stop microk8s.daemon-k8s-dqlite
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sudo tar -cpf /root/backend-pre-vacuum-$stamp.tar -C $kube backend
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sudo snap start microk8s.daemon-k8s-dqlite
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sudo ls -la /root/backend-pre-vacuum-$stamp.tar /root/dqlite-pre-vacuum-$stamp.tar.gz
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sudo microk8s status --wait-ready --timeout 300 >/dev/null && echo "microk8s is ready"
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echo "== letting the API server and controllers settle for a minute"
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sleep 60
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echo "== VACUUM"
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ps -o rss= -C k8s-dqlite | awk '{printf "k8s-dqlite RSS before: %.0f MB\n", $1/1024}'
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~/dqlite-vacuum -vacuum
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echo "== integrity check"
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$shell "PRAGMA integrity_check"
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ps -o rss= -C k8s-dqlite | awk '{printf "k8s-dqlite RSS after: %.0f MB\n", $1/1024}'
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echo "== $(date) done"
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