Migrate data into MySQL from bootstrap.

Use Heat Metadata to specify host and credentials to pull whole database
snapshot and setup Replication. Also include root credentials for use after
the snapshot has been applied.

Change-Id: Ie3aa92463d28db54a523f520c2b4cdfb528acf9d

elements/mysql-migration/README.md

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+Migrate data from another MySQL server into the local one using
+os-config-applier and os-refresh-config.
+
+Please note the migration process is *destructive* to any data currently
+in the MySQL database running on the target host. Safeguards are in
+place to ensure the process only happens once on any machine.
+
+Configuration
+-------------
+
+Pass in Heat Metadata with the following structure in the
+OpenStack::Config sub-key.
+
+    mysql:
+      users:
+        root:
+          username: rootuser
+          password: XXXXXXX
+        dump:
+          username: dumpuser
+          password: XXXXXXX
+    mysql-migration:
+      bootstrap_host: x.y.z
+      slave_user: slave-bot1
+      slave_password: XXXXXXXX
+
+The migration process assumes `dump` and `root` exist on the
+`bootstrap_host` and have access from this host.
+
+The `dump` user will be used to dump data from `bootstrap_host`. The
+`root` user will be used for localhost access after the database is
+migrated. If `slave_user` and `slave_password` are set to non-empty
+strings, replication will be setup against the `bootstrap_host` using
+this user/password combination.
+
+Special /root/.my.cnf
+---------------------
+
+As a convenience, we copy the given `dump` and `root` user names and
+passwords to /root/.my.cnf after migration. If this file is overwritten,
+they will also be available as /root/metadata.my.cnf

elements/mysql-migration/element-deps

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+mysql
+os-config-applier
+os-refresh-config

elements/mysql-migration/os-config-applier/etc/mysql/migration_default

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+MIGRATION_HOST={{mysql-migration.bootstrap_host}}
+MIGRATION_USER={{mysql-migration.slave_user}}
+MIGRATION_PASSWORD={{mysql-migration.slave_password}}
+MIGRATION_DUMP_USER={{mysql-migration.users.dump.username}}

elements/mysql-migration/os-config-applier/root/metadata.my.cnf

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+{{#mysql-migration.users.root}}
+[client]
+user={{username}}
+password={{password}}
+{{/mysql-migration.users.root}}
+{{#mysql-migration.users.dump}}
+[mysqldump]
+user={{username}}
+password={{password}}
+{{/mysql-migration.users.dump}}

elements/mysql-migration/os-refresh-config/migration.d/10-bootstrap-mysql

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+#!/bin/bash
+#
+# Copyright 2013 Hewlett-Packard Development Company, L.P.
+# All Rights Reserved.
+#
+# Licensed 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.
+
+set -eux
+
+# Quietly go away unless a migration has been asked for
+DEFAULTS=/etc/mysql/migration_default
+[ -e $DEFAULTS ] || exit 0
+source $DEFAULTS
+
+DONE_FILE=/etc/mysql/migration_done
+if [ -e $DONE_FILE ] ; then
+    echo migration from [$MIGRATION_HOST] already completed.
+    ls -l $DONE_FILE
+    exit 0
+fi
+
+# MySQL may be stopped pre-configuration, so try to start it
+if [ -d /etc/init ] ; then
+    # Upstart: During initial boot, mysql will start in parallel with os-refresh-config
+    # wait-for-state is a job that allows blocking until a particular state is reached.
+    start wait-for-state WAIT_FOR=mysql WAITER=$(basename $0) WAIT_FOREVER=Y TARGET_GOAL=start WAIT_STATE=running
+else
+    service mysql start || :
+fi
+
+local_mysql() {
+    if [ -e /root/.my.cnf ] ; then
+        mysql --defaults-extra-file=/root/.my.cnf "$@"
+    else
+        mysql "$@"
+    fi
+}
+
+local_mysql -e 'SHOW GRANTS'
+# This runs as root. We assume root has a .my.cnf or access
+# via localhost.
+if [ -n "$MIGRATION_HOST" ] ; then
+    local_mysql -e 'STOP SLAVE' || :
+    # If we are planning on setting up a full slave
+    if [ -n "$MIGRATION_USER" ] && [ -n "$MIGRATION_PASSWORD" ] ; then
+        local_mysql -e "CHANGE MASTER TO master_host='${MIGRATION_HOST}', master_user='${MIGRATION_USER}', master_password='${MIGRATION_PASSWORD}'"
+    fi
+    mysqldump --defaults-extra-file=/root/metadata.my.cnf \
+        -u $MIGRATION_DUMP_USER
+        --single-transaction \
+        --all-databases \
+        --master-data \
+        -h $MIGRATION_HOST | local_mysql
+
+    # After this following command, our ~/.my.cnf may stop working as its 
+    # password may change due to the dump loaded above.
+    local_mysql -e 'FLUSH PRIVILEGES'
+
+    # Now that database has been loaded, use creds that should match
+    cp -f /root/metadata.my.cnf /root/.my.cnf
+    # Now get the slave going if creds were provided
+    if [ -n "$MIGRATION_USER" ] && [ -n "$MIGRATION_PASSWORD" ] ; then
+        local_mysql -e "START SLAVE"
+    fi
+    touch $DONE_FILE
+fi