title: docker mysql in kuberneted ERROR 2005 (HY000): Unknown MySQL server host '' (-3)
body: <p>I'm trying to deploy a multi-container docker app (<a href="https://github.com/shadowHawkeye/eramba" rel="nofollow noreferrer">https://github.com/shadowHawkeye/eramba</a>). This is the yaml file I'm using to <code>kubectl apply -f</code></p>
  <p>The two images I have (one for DB and one for app) are built <code>docker build -t &lt;&gt; .</code> from the GitHub repo.</p>
  <p>The DB_ENV_MYSQL_HOST, I've tried both  and &lt;eramba-db.eramba-1&gt;</p>
  <pre><code>apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: eramba
    namespace: eramba-1
    labels:
     app: eramba               
  spec:
    replicas: 1
    selector:
      matchLabels:
        app: eramba
    template:
      metadata:
        labels:
          app: eramba
      spec:
        containers:
        - name: eramba
          image: docker.io/deveramba/eramba:latest
          ports:
          - containerPort: 80
          env:
          - name: DB_ENV_MYSQL_DATABASE
            value: &quot;eramba-db&quot;
          - name: DB_ENV_MYSQL_HOST
            value: &quot;eramba-host&quot;
          - name: DB_ENV_MYSQL_USER
            value: &quot;eramba&quot;
          - name: DB_ENV_MYSQL_PASSWORD
            value: &quot;password&quot;
          - name: DB_ENV_MYSQL_ROOT_PASSWORD
            value: &quot;password&quot;
          - name: ERAMBA_HOSTNAME
            value: localhost
  ---
  apiVersion: apps/v1
  kind: Deployment
  metadata:
    name: eramba-db
    namespace: eramba-1
    labels:
     app: eramba-db
  spec:
    replicas: 1
    selector:
      matchLabels:
        app: eramba-db
    template:
      metadata:
        labels:
          app: eramba-db
      spec:
        containers:
        - name: eramba-db
          image: docker.io/deveramba/eramba-db:latest
          ports:
          - containerPort: 3306
          env:
          - name: MYSQL_DATABASE
            value: &quot;eramba-db&quot;
          - name: MYSQL_USER
            value: &quot;eramba&quot;
          - name: MYSQL_PASSWORD
            value: &quot;password&quot;
          - name: MYSQL_ROOT_PASSWORD
            value: &quot;password&quot;
  ---
  apiVersion: v1
  kind: Service
  metadata:
    name: db
    namespace: eramba-1
  spec:
    selector:
      app: eramba-db
    ports:
      - name: sql
        port: 3306
        targetPort: 3306
  ---
  apiVersion: v1
  kind: Service
  metadata:
    name: eramba-np
    namespace: eramba-1
  spec:
    type: NodePort
    selector:
      app: eramba
    ports:
      - name: http
        port: 80
        targetPort: 80
        nodePort: 30045
  </code></pre>
  <p>The deployment looks like (pods and services output)</p>
  <pre><code>root@osboxes:/home/osboxes/manifests# kubectl get pods -n eramba-1
  NAME                         READY   STATUS    RESTARTS      AGE
  eramba-7f7c88c9d6-zqnzr      1/1     Running   2 (73s ago)   7m47s
  eramba-db-6c5fdfb7b8-wtgqd   1/1     Running   0             7m47s
  
  root@osboxes:/home/osboxes/manifests# kubectl get service -o wide -n eramba-1
  NAME        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE     SELECTOR
  db          ClusterIP   10.98.169.229   &lt;none&gt;        3306/TCP       3h31m   app=eramba-db
  eramba-np   NodePort    10.97.149.116   &lt;none&gt;        80:30045/TCP   3h31m   app=eramba
  </code></pre>
  <p>The problem is that kubectl logs &lt;&gt; is complaining unknown host Eramba-host. I've defined DB_ENV_MYSQL_HOST and MYSQL_HOST in both app and db deployments, respectively.</p>
  <pre><code>root@osboxes:/home/osboxes/manifests# kubectl logs eramba-7f7c88c9d6-zqnzr -n eramba-1
  [i] pre-exec.d - processing /scripts/pre-exec.d/010-apache.sh
  tail: can't open '/var/log/apache2/*log': No such file or directory
  [i] pre-exec.d - processing /scripts/pre-exec.d/020-eramba-initdb.sh
  [i] Waiting for database to setup...
  [i] Trying to connect to database: try 1...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 2...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 3...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 4...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 5...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 6...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  [i] Trying to connect to database: try 7...
  ERROR 2005 (HY000): Unknown MySQL server host 'eramba-host' (-3)
  </code></pre>
  <p>Here's the <code>kubectl logs</code> output for the db</p>
  <pre><code>root@osboxes:/home/osboxes/manifests# kubectl logs eramba-db-6c5fdfb7b8-wtgqd -n eramba-1
  2022-01-07 19:17:00+00:00 [Note] [Entrypoint]: Entrypoint script for MariaDB Server 1:10.6.5+maria~focal started.
  2022-01-07 19:17:00+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
  2022-01-07 19:17:00+00:00 [Note] [Entrypoint]: Entrypoint script for MariaDB Server 1:10.6.5+maria~focal started.
  2022-01-07 19:17:00+00:00 [Note] [Entrypoint]: Initializing database files
  2022-01-07 19:17:00 0 [Warning] You need to use --log-bin to make --expire-logs-days or --binlog-expire-logs-seconds work.
  
  
  PLEASE REMEMBER TO SET A PASSWORD FOR THE MariaDB root USER !
  To do so, start the server, then issue the following command:
  
  '/usr/bin/mysql_secure_installation'
  
  which will also give you the option of removing the test
  databases and anonymous user created by default.  This is
  strongly recommended for production servers.
  
  See the MariaDB Knowledgebase at https://mariadb.com/kb or the
  MySQL manual for more instructions.
  
  Please report any problems at https://mariadb.org/jira
  
  The latest information about MariaDB is available at https://mariadb.org/.
  You can find additional information about the MySQL part at:
  https://dev.mysql.com
  Consider joining MariaDB's strong and vibrant community:
  https://mariadb.org/get-involved/
  
  2022-01-07 19:17:01+00:00 [Note] [Entrypoint]: Database files initialized
  2022-01-07 19:17:01+00:00 [Note] [Entrypoint]: Starting temporary server
  2022-01-07 19:17:01+00:00 [Note] [Entrypoint]: Waiting for server startup
  2022-01-07 19:17:01 0 [Note] mariadbd (server 10.6.5-MariaDB-1:10.6.5+maria~focal) starting as process 96 ...
  2022-01-07 19:17:01 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
  2022-01-07 19:17:01 0 [Note] InnoDB: Number of pools: 1
  2022-01-07 19:17:01 0 [Note] InnoDB: Using crc32 + pclmulqdq instructions
  2022-01-07 19:17:01 0 [Note] mariadbd: O_TMPFILE is not supported on /tmp (disabling future attempts)
  2022-01-07 19:17:01 0 [Note] InnoDB: Using Linux native AIO
  2022-01-07 19:17:01 0 [Note] InnoDB: Initializing buffer pool, total size = 134217728, chunk size = 134217728
  2022-01-07 19:17:01 0 [Note] InnoDB: Completed initialization of buffer pool
  2022-01-07 19:17:01 0 [Note] InnoDB: 128 rollback segments are active.
  2022-01-07 19:17:01 0 [Note] InnoDB: Creating shared tablespace for temporary tables
  2022-01-07 19:17:01 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
  2022-01-07 19:17:01 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
  2022-01-07 19:17:01 0 [Note] InnoDB: 10.6.5 started; log sequence number 41361; transaction id 14
  2022-01-07 19:17:01 0 [Note] Plugin 'FEEDBACK' is disabled.
  2022-01-07 19:17:01 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
  2022-01-07 19:17:01 0 [Warning] You need to use --log-bin to make --expire-logs-days or --binlog-expire-logs-seconds work.
  2022-01-07 19:17:01 0 [Warning] 'user' entry 'root@eramba-db-6c5fdfb7b8-wtgqd' ignored in --skip-name-resolve mode.
  2022-01-07 19:17:01 0 [Warning] 'proxies_priv' entry '@% root@eramba-db-6c5fdfb7b8-wtgqd' ignored in --skip-name-resolve mode.
  2022-01-07 19:17:01 0 [Note] InnoDB: Buffer pool(s) load completed at 220107 19:17:01
  2022-01-07 19:17:01 0 [Note] mariadbd: ready for connections.
  Version: '10.6.5-MariaDB-1:10.6.5+maria~focal'  socket: '/run/mysqld/mysqld.sock'  port: 0  mariadb.org binary distribution
  2022-01-07 19:17:02+00:00 [Note] [Entrypoint]: Temporary server started.
  Warning: Unable to load '/usr/share/zoneinfo/leap-seconds.list' as time zone. Skipping it.
  Warning: Unable to load '/usr/share/zoneinfo/leapseconds' as time zone. Skipping it.
  Warning: Unable to load '/usr/share/zoneinfo/tzdata.zi' as time zone. Skipping it.
  2022-01-07 19:17:03 5 [Warning] 'proxies_priv' entry '@% root@eramba-db-6c5fdfb7b8-wtgqd' ignored in --skip-name-resolve mode.
  2022-01-07 19:17:03+00:00 [Note] [Entrypoint]: Creating database eramba-db
  2022-01-07 19:17:03+00:00 [Note] [Entrypoint]: Creating user eramba
  2022-01-07 19:17:03+00:00 [Note] [Entrypoint]: Giving user eramba access to schema eramba-db
  
  2022-01-07 19:17:03+00:00 [Note] [Entrypoint]: Stopping temporary server
  2022-01-07 19:17:03 0 [Note] mariadbd (initiated by: root[root] @ localhost []): Normal shutdown
  2022-01-07 19:17:03 0 [Note] InnoDB: FTS optimize thread exiting.
  2022-01-07 19:17:03 0 [Note] InnoDB: Starting shutdown...
  2022-01-07 19:17:03 0 [Note] InnoDB: Dumping buffer pool(s) to /var/lib/mysql/ib_buffer_pool
  2022-01-07 19:17:03 0 [Note] InnoDB: Buffer pool(s) dump completed at 220107 19:17:03
  2022-01-07 19:17:04 0 [Note] InnoDB: Removed temporary tablespace data file: &quot;./ibtmp1&quot;
  2022-01-07 19:17:04 0 [Note] InnoDB: Shutdown completed; log sequence number 42335; transaction id 15
  2022-01-07 19:17:04 0 [Note] mariadbd: Shutdown complete
  
  2022-01-07 19:17:04+00:00 [Note] [Entrypoint]: Temporary server stopped
  
  2022-01-07 19:17:04+00:00 [Note] [Entrypoint]: MariaDB init process done. Ready for start up.
  
  2022-01-07 19:17:04 0 [Note] mariadbd (server 10.6.5-MariaDB-1:10.6.5+maria~focal) starting as process 1 ...
  2022-01-07 19:17:04 0 [Note] InnoDB: Compressed tables use zlib 1.2.11
  2022-01-07 19:17:04 0 [Note] InnoDB: Number of pools: 1
  2022-01-07 19:17:04 0 [Note] InnoDB: Using crc32 + pclmulqdq instructions
  2022-01-07 19:17:04 0 [Note] mariadbd: O_TMPFILE is not supported on /tmp (disabling future attempts)
  2022-01-07 19:17:05 0 [Note] InnoDB: Using Linux native AIO
  2022-01-07 19:17:05 0 [Note] InnoDB: Initializing buffer pool, total size = 134217728, chunk size = 134217728
  2022-01-07 19:17:05 0 [Note] InnoDB: Completed initialization of buffer pool
  2022-01-07 19:17:05 0 [Note] InnoDB: 128 rollback segments are active.
  2022-01-07 19:17:05 0 [Note] InnoDB: Creating shared tablespace for temporary tables
  2022-01-07 19:17:05 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
  2022-01-07 19:17:05 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
  2022-01-07 19:17:05 0 [Note] InnoDB: 10.6.5 started; log sequence number 42335; transaction id 14
  2022-01-07 19:17:05 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
  2022-01-07 19:17:05 0 [Note] Plugin 'FEEDBACK' is disabled.
  2022-01-07 19:17:05 0 [Warning] You need to use --log-bin to make --expire-logs-days or --binlog-expire-logs-seconds work.
  2022-01-07 19:17:05 0 [Note] InnoDB: Buffer pool(s) load completed at 220107 19:17:05
  2022-01-07 19:17:05 0 [Note] Server socket created on IP: '0.0.0.0'.
  2022-01-07 19:17:05 0 [Note] Server socket created on IP: '::'.
  2022-01-07 19:17:05 0 [Warning] 'proxies_priv' entry '@% root@eramba-db-6c5fdfb7b8-wtgqd' ignored in --skip-name-resolve mode.
  2022-01-07 19:17:05 0 [Note] mariadbd: ready for connections.
  Version: '10.6.5-MariaDB-1:10.6.5+maria~focal'  socket: '/run/mysqld/mysqld.sock'  port: 3306  mariadb.org binary distribution
  </code></pre>