mysql update warnings (#212)

* mysql-quirk
Co-authored-by: Rohit Yadav <rohit.yadav@shapeblue.com>

* Update source/upgrading/upgrade/mysql.rst

Co-authored-by: Andrija Panic <45762285+andrijapanicsb@users.noreply.github.com>

Co-authored-by: Daan Hoogland <dahn@onecht.net>
Co-authored-by: Andrija Panic <45762285+andrijapanicsb@users.noreply.github.com>

Author: 3 people

source/upgrading/index.rst

@@ -31,12 +31,13 @@ release.  Please read through all sections carefully before starting.
 .. note::
    For information on the API changes and issues fixed in this release, please see the Release Notes section of the documentation
 
-
 Contents:
 
 .. toctree::
    :maxdepth: 1
 
+   upgrade/mysql
+   upgrade/valid_source
    upgrade/upgrade-4.15
    upgrade/upgrade-4.14
    upgrade/upgrade-4.13
@@ -55,4 +56,3 @@ Contents:
 ..   upgrade/upgrade-4.0
 ..   upgrade/upgrade-3.0.x
 ..   upgrade/upgrade-2.2.14
-   upgrade/valid_source

source/upgrading/upgrade/mysql.rst

@@ -0,0 +1,32 @@
+.. Licensed to the Apache Software Foundation (ASF) under one
+   or more contributor license agreements.  See the NOTICE file
+   distributed with this work for additional information#
+   regarding copyright ownership.  The ASF licenses this file
+   to you under the Apache License, Version 2.0 (the
+   "License"); you may not use this file except in compliance
+   with the License.  You may obtain a copy of the License at
+   http://www.apache.org/licenses/LICENSE-2.0
+   Unless required by applicable law or agreed to in writing,
+   software distributed under the License is distributed on an
+   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+   KIND, either express or implied.  See the License for the
+   specific language governing permissions and limitations
+   under the License.
+
+MySQL upgrade problems
+======================
+
+With certain MySQL versions (see below), issues have been seen with "cloud.nics" table's 
+column type (which was not updated properly during CloudStack upgrades, due to MySQL limitations),
+which eventually may lead to exception seen in the management server logs, causing users to
+not be able to start any VM.
+
+The following SQL statement needs to be manually executed in order to fix such issue:
+
+   .. parsed-literal::
+ALTER TABLE nics MODIFY COLUMN update_time timestamp DEFAULT CURRENT_TIMESTAMP;
+
+The issue is known to affect the following MySQL server versions:
+
+ -  5.7.34 or later
+ -  8+