Chapter 5 of the dmz-web documentation · headings are numbered like the cheat sheets · index: Wiki

• Table of contents
• 5.1 Services
• 5.2 Listing / inspecting
• 5.3 Environment variables inside a container
• 5.4 Secrets
• 5.5 Fixing a secret that has a trailing \n (legacy WordPress sites)
• 5.6 Database engines and version upgrades

5.1 Services¶

systemctl --user daemon-reload                        # after editing any Quadlet file
systemctl --user list-units 'db-*' 'site-*' 'net-*' 'nginx-proxy-manager*'
systemctl --user status  db-<name>.service site-<name>.service
systemctl --user restart db-<name>.service site-<name>.service
journalctl --user -u site-<name>.service -e
/usr/libexec/podman/quadlet -dryrun -user             # validate Quadlet syntax

5.2 Listing / inspecting¶

podman ps -a
podman network ls ; podman volume ls ; podman secret ls
podman inspect <ctr> --format '{{.ImageName}}'
podman inspect <ctr> --format '{{range .Mounts}}{{.Name}} -> {{.Destination}}{{"\n"}}{{end}}'
podman inspect <ctr> | jq '.[0].Config.Env'
podman logs -f <ctr>
podman exec -it <ctr> bash                            # root shell inside, no password

5.3 Environment variables inside a container¶

podman exec <ctr> printenv
podman exec <ctr> printenv | grep -iE 'ROOT|PASSWORD|KEY'
podman exec <ctr> printenv MYSQL_ROOT_PASSWORD | od -c | tail -3   # reveals a stray trailing \n

5.4 Secrets¶

Injected as env at container start (Secret=<secret>,type=env,target=VAR).
MariaDB/PostgreSQL only read their *_PASSWORD env on first
initialisation of an empty data dir; afterwards the env var is inert and the
real password is whatever is in the DB.

podman secret inspect --showsecret <secret>
podman secret inspect --showsecret --format '{{.SecretData}}' <secret>

# always create WITHOUT a trailing newline
printf '%s' 'VALUE' | podman secret create <secret> -
printf '%s' "$(openssl rand -base64 32)" | podman secret create <secret> -

# replace: rm + create, then restart the consumers
podman secret rm <secret> && printf '%s' 'VALUE' | podman secret create <secret> -

5.5 Fixing a secret that has a trailing \n (legacy WordPress sites)¶

cat > ~/tmp/fixpw.sh <<'EOF'
ROOTPW="$(printf '%s' "$MYSQL_ROOT_PASSWORD")"   # $(...) strips the trailing \n
WPPW="$(printf '%s' "$MYSQL_PASSWORD")"
mariadb -uroot -p"$MYSQL_ROOT_PASSWORD" <<SQL
ALTER USER 'root'@'localhost' IDENTIFIED BY '$ROOTPW';
ALTER USER 'root'@'%'         IDENTIFIED BY '$ROOTPW';
ALTER USER 'wordpress'@'%'    IDENTIFIED BY '$WPPW';
FLUSH PRIVILEGES;
SQL
EOF
podman exec -i db-<name> sh < ~/tmp/fixpw.sh
for s in <name>-db-root-password <name>-db-password; do
  v="$(podman secret inspect --showsecret --format '{{.SecretData}}' "$s")"
  podman secret rm "$s"; printf '%s' "$v" | podman secret create "$s" -
done
systemctl --user restart db-<name>.service site-<name>.service   # run back to back with the SQL half

5.6 Database engines and version upgrades¶

Every stack has its own DB container; the engine and version are in the DB unit (Image=). Rule
for all of them: dump first, change one Image= line in the repo copy, commit, copy the unit,
daemon-reload, restart, check (§3.1.7 and §3.1.6, same procedure as the Snipe-IT image upgrade in §4.3). Which
of the two cases applies depends on the kind of jump.

A dump that was never restored is not a backup: restore it once into a scratch container and look
at the data before you depend on it. Keep the old image tag and the old volume until the new
version has run for a few days; then remove them.

Source: dmz-web-podman-cheatsheet.md v1.8 in the dmz-web-deploy repo (Releases). Edit the wiki and the repo copy together.