mysqld not starting up

I installed mysql on ubuntu. mysqld does not startup with the following errors - 2017-04-16T00:22:35.320639Z 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql/ib_buffer_pool 2017-04-16T00:22:35.321014Z 0 [Note] InnoDB: Buffer pool(s) load completed at 170415 19:22:35 2017-04-16T00:22:35.321036Z 0 [Note] Plugin 'FEDERATED' is disabled. mysqld: Table 'mysql.plugin' doesn't exist 2017-04-16T00:22:35.321354Z 0 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it. 2017-04-16T00:22:35.322301Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened. 2017-04-16T00:22:35.322490Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without certificate and private key 2017-04-16T00:22:35.323247Z 0 [Note] Server hostname (bind-address): '*'; port: 3306 2017-04-16T00:22:35.323361Z 0 [Note] IPv6 is available. 2017-04-16T00:22:35.323379Z 0 [Note] - '::' resolves to '::'; 2017-04-16T00:22:35.323411Z 0 [Note] Server socket created on IP: '::'. 2017-04-16T00:22:35.323450Z 0 [ERROR] Could not create unix socket lock file /var/run/mysqld/mysqld.sock.lock. 2017-04-16T00:22:35.323464Z 0 [ERROR] Unable to setup unix socket lock file. 2017-04-16T00:22:35.323476Z 0 [ERROR] Aborting 2017-04-16T00:22:35.323497Z 0 [Note] Binlog end 2017-04-16T00:22:35.323545Z 0 [Note] Shutting down plugin 'ngram' Please help. Thanks