Marks mysql slave read-only

When a slave is attached to a master site, this change will
mark the slave site as read-only to prevent the slave site
from being updated by users.  Only users with root privileges
or slave priveleges will be able to update the database.

Change-Id: Idb6c54b85a23af9a468ff9d62b3110fa72ff7da0
Closes-bug: #1359392

trove/guestagent/strategies/replication/mysql_binlog.py

@@ -39,6 +39,7 @@ SLAVE_CONFIG = """
 [mysqld]
 log_bin = /var/lib/mysql/mysql-bin.log
 relay_log = /var/lib/mysql/mysql-relay-bin.log
+read_only = true
 """
 
 REPL_BACKUP_NAMESPACE = 'trove.guestagent.strategies.backup.mysql_impl'

trove/tests/api/replication.py

@@ -116,6 +116,13 @@ class VerifySlave(object):
         poll_until(slave_is_running())
 
     @test(depends_on=[test_correctly_started_replication])
+    def test_slave_is_read_only(self):
+        cmd = "mysql -BNq -e \\\'select @@read_only\\\'"
+        server = create_server_connection(slave_instance.id)
+        stdout, stderr = server.execute(cmd)
+        assert_equal(stdout, "1\n")
+
+    @test(depends_on=[test_slave_is_read_only])
     def test_create_db_on_master(self):
         databases = [{'name': slave_instance.replicated_db}]
         instance_info.dbaas.databases.create(instance_info.id, databases)
@@ -174,6 +181,16 @@ class DetachReplica(object):
 
         poll_until(slave_is_running(False))
 
+    @test(depends_on=[test_detach_replica])
+    def test_slave_is_not_read_only(self):
+        if CONFIG.fake_mode:
+            raise SkipTest("Test not_read_only not supported in fake mode")
+
+        cmd = "mysql -BNq -e \\\'select @@read_only\\\'"
+        server = create_server_connection(slave_instance.id)
+        stdout, stderr = server.execute(cmd)
+        assert_equal(stdout, "0\n")
+
 
 @test(groups=[GROUP],
       depends_on=[WaitForCreateSlaveToFinish],