Fix Wordpress Redis Docker/Kubernetes: "ERR unknown command 'FLUSHDB'"

If you use for example redis bitnami helm chart with Replication, FLUSHDB is not possible. To fix this you can make follow this guide.

Adjust your wp-config.php in this style:

define('WP_REDIS_CLIENT', 'phpredis');
define('WP_REDIS_HOST', 'redis');
define('WP_REDIS_PORT', 6379);
define('WP_REDIS_PASSWORD', getenv_docker('REDIS_PASSWORD', 'not_defined'));
define('WP_REDIS_PREFIX', 'wordpress:');

And then enter the cli-container and execute

wp config set WP_CACHE true --raw --allow-root
wp eval "copy(WP_CONTENT_DIR . '/plugins/redis-cache/includes/object-cache.php', WP_CONTENT_DIR . '/object-cache.php');" --allow-root
wp redis status --allow-root