Comment 3 for bug 1623440

The mysqld won't launch because it appears to see another process using port 3306 and the update to mysql-server-5.7 fails. - from mysql error log file:

2016-09-15T02:18:17.979012Z 0 [Note] /usr/sbin/mysqld (mysqld 5.7.13-0ubuntu0.16.04.2) starting as process 23533 ...
2016-09-15T02:18:17.983324Z 0 [Note] InnoDB: PUNCH HOLE support available
2016-09-15T02:18:17.983359Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2016-09-15T02:18:17.983369Z 0 [Note] InnoDB: Uses event mutexes
2016-09-15T02:18:17.983376Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
2016-09-15T02:18:17.983383Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.8
2016-09-15T02:18:17.983390Z 0 [Note] InnoDB: Using Linux native AIO
2016-09-15T02:18:17.983570Z 0 [Note] InnoDB: Number of pools: 1
2016-09-15T02:18:17.983656Z 0 [Note] InnoDB: Using CPU crc32 instructions
2016-09-15T02:18:17.984766Z 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2016-09-15T02:18:17.992421Z 0 [Note] InnoDB: Completed initialization of buffer pool
2016-09-15T02:18:17.994116Z 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2016-09-15T02:18:18.005405Z 0 [Note] InnoDB: Highest supported file format is Barracuda.
2016-09-15T02:18:18.618634Z 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2016-09-15T02:18:18.618709Z 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2016-09-15T02:18:20.536298Z 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2016-09-15T02:18:20.553687Z 0 [Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
2016-09-15T02:18:20.553726Z 0 [Note] InnoDB: 32 non-redo rollback segment(s) are active.
2016-09-15T02:18:20.561468Z 0 [Note] InnoDB: 5.7.13 started; log sequence number 2640189
2016-09-15T02:18:20.561675Z 0 [Note] Plugin 'FEDERATED' is disabled.
2016-09-15T02:18:20.564973Z 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool
2016-09-15T02:18:20.565308Z 0 [Note] InnoDB: Buffer pool(s) load completed at 160914 22:18:20
2016-09-15T02:18:20.568395Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without certificate and private key
2016-09-15T02:18:20.568420Z 0 [Note] Server hostname (bind-address): '192.168.100.16'; port: 3306
2016-09-15T02:18:20.568434Z 0 [Note] - '192.168.100.16' resolves to '192.168.100.16';
2016-09-15T02:18:20.568460Z 0 [Note] Server socket created on IP: '192.168.100.16'.
2016-09-15T02:18:20.568478Z 0 [ERROR] Can't start server: Bind on TCP/IP port: Cannot assign requested address
2016-09-15T02:18:20.568483Z 0 [ERROR] Do you already have another mysqld server running on port: 3306 ?
2016-09-15T02:18:20.568497Z 0 [ERROR] Aborting