This topic reviews how to migrate MySQL, PostgreSQL, and MongoDB database applications from OpenShift version 2 (v2) to OpenShift version 3 (v3).
| v2 | v3 |
|---|---|
MongoDB: 2.4 |
MongoDB: 2.4, 2.6 |
MySQL: 5.5 |
MySQL: 5.5, 5.6 |
PostgreSQL: 9.2 |
PostgreSQL: 9.2, 9.4 |
Export all databases to a dump file and copy it to a local machine (into the current directory):
$ rhc ssh <v2_application_name>
$ mysqldump --skip-lock-tables -h $OPENSHIFT_MYSQL_DB_HOST -P ${OPENSHIFT_MYSQL_DB_PORT:-3306} -u ${OPENSHIFT_MYSQL_DB_USERNAME:-'admin'} \
--password="$OPENSHIFT_MYSQL_DB_PASSWORD" --all-databases > ~/app-root/data/all.sql
$ exit
Download dbdump to your local machine:
$ mkdir mysqldumpdir $ rhc scp -a <v2_application_name> download mysqldumpdir app-root/data/all.sql
Create a v3 mysql-persistent pod from template:
$ oc new-app mysql-persistent -p \ MYSQL_USER=<your_V2_mysql_username> -p \ MYSQL_PASSWORD=<your_v2_mysql_password> -p MYSQL_DATABASE=<your_v2_database_name>
Check to see if the pod is ready to use:
$ oc get pods
When the pod is up and running, copy database archive files to your v3 MySQL pod:
$ oc rsync /local/mysqldumpdir <mysql_pod_name>:/var/lib/mysql/data
Restore the database in the v3 running pod:
$ oc rsh <mysql_pod> $ cd /var/lib/mysql/data/mysqldumpdir
In v3, to restore databases you need to access MySQL as root user.
In v2, the $OPENSHIFT_MYSQL_DB_USERNAME had full privileges on all
databases. In v3, you must grant privileges to $MYSQL_USER for each
database.
$ mysql -u root $ source all.sql
Grant all privileges on <dbname> to <your_v2_username>@localhost, then flush
privileges.
Remove the dump directory from the pod:
$ cd ../; rm -rf /var/lib/mysql/data/mysqldumpdir
Supported MySQL Environment Variables
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Back up the v2 PostgreSQL database from the gear:
$ rhc ssh -a <v2-application_name> $ mkdir ~/app-root/data/tmp $ pg_dump <database_name> | gzip > ~/app-root/data/tmp/<database_name>.gz
Extract the backup file back to your local machine:
$ rhc scp -a <v2_application_name> download <local_dest> app-root/data/tmp/<db-name>.gz $ gzip -d <database-name>.gz
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Save the backup file to a separate folder for step 4. |
Create the PostgreSQL service using the v2 application database name, user name and password to create the new service:
$ oc new-app postgresql-persistent -p POSTGRESQL_DATABASE=dbname -p POSTGRESQL_PASSWORD=password -p POSTGRESQL_USER=username
Check to see if the pod is ready to use:
$ oc get pods
When the pod is up and running, sync the backup directory to pod:
$ oc rsync /local/path/to/dir <postgresql_pod_name>:/var/lib/pgsql/data
Remotely access the pod:
$ oc rsh <pod_name>
Restore the database:
psql dbname < /var/lib/pgsql/data/<database_backup_file>
Remove all backup files that are no longer needed:
$ rm /var/lib/pgsql/data/<database-backup-file>
Supported PostgreSQL Environment Variables
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Remotely access the v2 application via the ssh command:
$ rhc ssh <v2_application_name>
Run mongodump, specifying a single database with -d <database_name> -c
<collections>. Without those options, dump all databases. Each database is
dumped in its own directory:
$ mongodump -h $OPENSHIFT_MONGODB_DB_HOST -o app-root/repo/mydbdump -u 'admin' -p $OPENSHIFT_MONGODB_DB_PASSWORD $ cd app-root/repo/mydbdump/<database_name>; tar -cvzf dbname.tar.gz $ exit
Download dbdump to a local machine in the mongodump directory:
$ mkdir mongodump $ rhc scp -a <v2 appname> download mongodump \ app-root/repo/mydbdump/<dbname>/dbname.tar.gz
Start a MongoDB pod in v3. Because the latest image (3.2.6) does not include
mongo-tools, to use mongorestore or mongoimport commands you need to edit
the default mongodb-persistent template to specify the image tag that contains
the mongo-tools, “mongodb:2.4”. For that reason, the following oc export
command and edit are necessary:
$ oc export template mongodb-persistent -n openshift -o json > mongodb-24persistent.json
Edit L80 of mongodb-24persistent.json; replace mongodb:latest with mongodb:2.4.
$ oc new-app --template=mongodb-persistent -n <project-name-that-template-was-created-in> \ MONGODB_USER=user_from_v2_app -p \ MONGODB_PASSWORD=password_from_v2_db -p \ MONGODB_DATABASE=v2_dbname -p \ MONGODB_ADMIN_PASSWORD=password_from_v2_db $ oc get pods
When the mongodb pod is up and running, copy the database archive files to the v3 MongoDB pod:
$ oc rsync local/path/to/mongodump <mongodb_pod_name>:/var/lib/mongodb/data $ oc rsh <mongodb_pod>
In the MongoDB pod, complete the following for each database you want to restore:
$ cd /var/lib/mongodb/data/mongodump $ tar -xzvf dbname.tar.gz $ mongorestore -u $MONGODB_USER -p $MONGODB_PASSWORD -d dbname -v /var/lib/mongodb/data/mongodump
Check if the database is restored:
$ mongo admin -u $MONGODB_USER -p $MONGODB_ADMIN_PASSWORD $ use dbname $ show collections $ exit
Remove the mongodump directory from the pod:
$ rm -rf /var/lib/mongodb/data/mongodump
Supported MongoDB Environment Variables
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