Look in more directories for upgrade binaries

This makes upgrades compatible with images from other distros.

Issue: PGO-864

Author: cbandy

internal/controller/pgupgrade/jobs.go

@@ -21,6 +21,7 @@ import (
 	"github.com/crunchydata/postgres-operator/internal/feature"
 	"github.com/crunchydata/postgres-operator/internal/initialize"
 	"github.com/crunchydata/postgres-operator/internal/naming"
+	"github.com/crunchydata/postgres-operator/internal/postgres"
 	"github.com/crunchydata/postgres-operator/internal/shell"
 	"github.com/crunchydata/postgres-operator/pkg/apis/postgres-operator.crunchydata.com/v1beta1"
 )
@@ -80,11 +81,14 @@ func upgradeCommand(spec *v1beta1.PGUpgradeSettings, fetchKeyCommand string) []s
 		// - https://cwrap.org/nss_wrapper.html
 		`export LD_PRELOAD='libnss_wrapper.so' NSS_WRAPPER_GROUP NSS_WRAPPER_PASSWD`,
 
-		// Expect Postgres executables at the Red Hat paths.
+		// Find directories that contain the desired Postgres executables.
+		`old_bin=$(` + postgres.ShellPath(oldVersion) + ` && command -v postgres)`,
+		`old_bin="${old_bin%/postgres}"`,
+		`new_bin=$(` + postgres.ShellPath(newVersion) + ` && command -v initdb)`,
+		`new_bin="${new_bin%/initdb}"`,
+
 		`old_data="${data_volume}/pg${old_version}"`,
 		`new_data="${data_volume}/pg${new_version}"`,
-		`old_bin="/usr/pgsql-${old_version}/bin"`,
-		`new_bin="/usr/pgsql-${new_version}/bin"`,
 
 		// Below is the pg_upgrade script used to upgrade a PostgresCluster from
 		// one major version to another. Additional information concerning the
@@ -243,7 +247,7 @@ func removeDataCommand(upgrade *v1beta1.PGUpgrade) []string {
 		`delete() (set -x && rm -rf -- "$@")`,
 
 		`old_data="${data_volume}/pg${old_version}"`,
-		`control=$(LC_ALL=C /usr/pgsql-${old_version}/bin/pg_controldata "${old_data}")`,
+		`control=$(` + postgres.ShellPath(oldVersion) + ` && LC_ALL=C pg_controldata "${old_data}")`,
 		`read -r state <<< "${control##*cluster state:}"`,
 
 		// We expect exactly one state for a replica that has been stopped.

internal/controller/pgupgrade/jobs_test.go

@@ -209,10 +209,12 @@ spec:
           (sed "/^postgres:x:/ d; /^[^:]*:x:${uid}:/ d" /etc/passwd
           echo "postgres:x:${uid}:${gid%% *}::${data_volume}:") > "${NSS_WRAPPER_PASSWD}"
           export LD_PRELOAD='libnss_wrapper.so' NSS_WRAPPER_GROUP NSS_WRAPPER_PASSWD
+          old_bin=$(PATH="/usr/lib/postgresql/19/bin:/usr/libexec/postgresql19:/usr/pgsql-19/bin${PATH+:${PATH}}" && command -v postgres)
+          old_bin="${old_bin%/postgres}"
+          new_bin=$(PATH="/usr/lib/postgresql/25/bin:/usr/libexec/postgresql25:/usr/pgsql-25/bin${PATH+:${PATH}}" && command -v initdb)
+          new_bin="${new_bin%/initdb}"
           old_data="${data_volume}/pg${old_version}"
           new_data="${data_volume}/pg${new_version}"
-          old_bin="/usr/pgsql-${old_version}/bin"
-          new_bin="/usr/pgsql-${new_version}/bin"
           cd "${data_volume}" || exit
           section 'Initializing new data directory...'
           PGDATA="${new_data}" "${new_bin}/initdb" --data-checksums
@@ -347,7 +349,7 @@ spec:
           printf 'Removing PostgreSQL %s data...\n\n' "$@"
           delete() (set -x && rm -rf -- "$@")
           old_data="${data_volume}/pg${old_version}"
-          control=$(LC_ALL=C /usr/pgsql-${old_version}/bin/pg_controldata "${old_data}")
+          control=$(PATH="/usr/lib/postgresql/19/bin:/usr/libexec/postgresql19:/usr/pgsql-19/bin${PATH+:${PATH}}" && LC_ALL=C pg_controldata "${old_data}")
           read -r state <<< "${control##*cluster state:}"
           [[ "${state}" == 'shut down in recovery' ]] || { printf >&2 'Unexpected state! %q\n' "${state}"; exit 1; }
           delete "${old_data}/pg_wal/"

internal/postgres/config.go

@@ -264,6 +264,17 @@ func Environment(cluster *v1beta1.PostgresCluster) []corev1.EnvVar {
 	}
 }
 
+// ShellPath returns a POSIX shell command that prepends typical Postgres executable paths to the PATH variable.
+func ShellPath(postgresVersion int32) string {
+	return fmt.Sprintf(`PATH="`+
+		strings.Join([]string{
+			`/usr/lib/postgresql/%[1]d/bin`, // Debian
+			`/usr/libexec/postgresql%[1]d`,  // Alpine
+			`/usr/pgsql-%[1]d/bin`,          // Red Hat
+		}, ":")+
+		`${PATH+:${PATH}}"`, postgresVersion)
+}
+
 // reloadCommand returns an entrypoint that convinces PostgreSQL to reload
 // certificate files when they change. The process will appear as name in `ps`
 // and `top`.