Check environment before starting Postgres major upgrade

This leaves the disk untouched when the upgrade image cannot support the
requested upgrade.

Issue: PGO-300
See: 406e069

Author: cbandy

internal/controller/pgupgrade/jobs.go

@@ -49,7 +49,7 @@ func upgradeCommand(spec *v1beta1.PGUpgradeSettings, fetchKeyCommand string) []s
 	newVersion := spec.ToPostgresVersion
 
 	// if the fetch key command is set for TDE, provide the value during initialization
-	initdb := `/usr/pgsql-"${new_version}"/bin/initdb -k -D /pgdata/pg"${new_version}"`
+	initdb := `/usr/pgsql-"${new_version}"/bin/initdb --allow-group-access -k -D /pgdata/pg"${new_version}"`
 	if fetchKeyCommand != "" {
 		initdb += ` --encryption-key-command "` + fetchKeyCommand + `"`
 	}
@@ -80,6 +80,12 @@ func upgradeCommand(spec *v1beta1.PGUpgradeSettings, fetchKeyCommand string) []s
 		// Enable nss_wrapper so the current UID and GID resolve to "postgres".
 		// - https://cwrap.org/nss_wrapper.html
 		`export LD_PRELOAD='libnss_wrapper.so' NSS_WRAPPER_GROUP NSS_WRAPPER_PASSWD`,
+		`id; [[ "$(id -nu)" == 'postgres' && "$(id -ng)" == 'postgres' ]]`,
+
+		// Expect Postgres executables at the Red Hat paths.
+		`[[ -x /usr/pgsql-"${old_version}"/bin/postgres ]]`,
+		`[[ -x /usr/pgsql-"${new_version}"/bin/initdb ]]`,
+		`[[ -d /pgdata/pg"${old_version}" ]]`,
 
 		// Below is the pg_upgrade script used to upgrade a PostgresCluster from
 		// one major version to another. Additional information concerning the

internal/controller/pgupgrade/jobs_test.go

@@ -208,11 +208,15 @@ spec:
           (sed "/^postgres:x:/ d; /^[^:]*:x:${uid}:/ d" /etc/passwd
           echo "postgres:x:${uid}:${gid%% *}::${data_volume}:") > "${NSS_WRAPPER_PASSWD}"
           export LD_PRELOAD='libnss_wrapper.so' NSS_WRAPPER_GROUP NSS_WRAPPER_PASSWD
+          id; [[ "$(id -nu)" == 'postgres' && "$(id -ng)" == 'postgres' ]]
+          [[ -x /usr/pgsql-"${old_version}"/bin/postgres ]]
+          [[ -x /usr/pgsql-"${new_version}"/bin/initdb ]]
+          [[ -d /pgdata/pg"${old_version}" ]]
           cd /pgdata || exit
           echo -e "Step 1: Making new pgdata directory...\n"
           mkdir /pgdata/pg"${new_version}"
           echo -e "Step 2: Initializing new pgdata directory...\n"
-          /usr/pgsql-"${new_version}"/bin/initdb -k -D /pgdata/pg"${new_version}"
+          /usr/pgsql-"${new_version}"/bin/initdb --allow-group-access -k -D /pgdata/pg"${new_version}"
           echo -e "\nStep 3: Setting the expected permissions on the old pgdata directory...\n"
           chmod 750 /pgdata/pg"${old_version}"
           echo -e "Step 4: Copying shared_preload_libraries setting to new postgresql.conf file...\n"
@@ -263,7 +267,7 @@ status: {}
 
 	tdeJob := reconciler.generateUpgradeJob(ctx, upgrade, startup, "echo testKey")
 	assert.Assert(t, cmp.MarshalContains(tdeJob,
-		`/usr/pgsql-"${new_version}"/bin/initdb -k -D /pgdata/pg"${new_version}" --encryption-key-command "echo testKey"`))
+		`/usr/pgsql-"${new_version}"/bin/initdb --allow-group-access -k -D /pgdata/pg"${new_version}" --encryption-key-command "echo testKey"`))
 }
 
 func TestGenerateRemoveDataJob(t *testing.T) {