Few days ago, I changed my personal server, with all my data, to another one. On this new one, I choose to use Docker to deploy all my old stuff, including this web site. When investigating throught Docker, I thought it was nice to explain the migration from my old server to my new one !<\/p>\n
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When I installed my previous server, years ago, I did not have any idea and knowlegde about Docker. So, when I had to install my previous server, I went throught internet and check about installing mysql, apache, and deploying wordpress. Since I work with Docker, I have a whole new way to do that ! I will not explain how to install Docker, cause there is another post dealing with that part !<\/p>\n
Knowing the way to retrieve images from external repository, just execute the pull command on mysql package (found it using\u00a0https:\/\/hub.docker.com\/) :<\/p>\n
docker pull mysql<\/pre>\nWaiting from Docker to download and extract the image, then you are ready to play with mysql !<\/p>\n
Adding user to store mysql data<\/h2>\n
I choose to create a user per application I will deploy using Docker. Let’s create a mysql user, which will store all data from mysql instance, and create associated directory :<\/p>\n
useradd mysql\r\nsu - mysql\r\nmkdir data<\/pre>\nDeploying mysql using Docker<\/h2>\n
Ok, we have the mysql image on our local repository, we have the directory to store data, all we need know is to deploy mysql using Docker ! To do that, just execute the “docker run” and specify the mysql image :<\/p>\n
docker run --name mysql-instance \\\r\n -v \/home\/mysql\/data:\/var\/lib\/mysql \\\r\n -e MYSQL_ROOT_PASSWORD=<my root password> \\\r\n --memory=512m \\\r\n -d mysql:latest<\/pre>\nCommand line explanations :<\/p>\n
root<\/code>\u00a0superuser account. In the above example, it was set to\u00a0my-secret-pw<\/code>.<\/em>“,<\/li>\n- -d \/ –detach : “Run container in background and print container ID<\/em>“.<\/li>\n<\/ul>\n
Verify that mysql is running<\/h2>\n
Docker implements a command to know all processes actually running on Docker instance, by using the “docker ps” command. Let’s see what is returned by this specific command :<\/p>\n
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES \r\n902871f958c1 mysql:latest \"docker-entrypoint.s 2 days ago Up 34 hours 3306\/tcp mysql-instance<\/pre>\nMysql is running, we will be able to query it using container ip or the link function !<\/p>\n
Retrieving and deploying wordpress<\/h1>\nRetrieving wordpress image to Docker<\/h2>\n
Same way as mysql image, I used the pull command specifying wordpress :<\/p>\n
docker pull wordpress<\/pre>\nDeploying wordpress using Docker<\/h2>\n
WordPress image is retrieved, let’s deploy it.<\/p>\n
docker run --name blog --link mysql-instance:mysql -p 9083:80 -d wordpress<\/pre>\nCommand line explanations :<\/p>\n
\n- –link : from the official documentation (https:\/\/docs.docker.com\/engine\/userguide\/networking\/default_network\/dockerlinks\/#communication-across-links), “Links allow containers to discover each other and securely transfer information about one container to another container. When you set up a link, you create a conduit between a source container and a recipient container. The recipient can then access select data about the source.<\/em>“. With this parameter, my wordpress container will be able to consume data from my mysql container ! The mysql instance, in the wordpress container, will be knowned as “mysql”,<\/li>\n
- -p \/ –publish : this argument specify which port I will query to query wordpress on port 80. I choose the port 9083 cause I have several applications using port 80.<\/li>\n<\/ul>\n
I just check my applications status using the “docker ps” command :<\/p>\n
CONTAINER ID IMAGE COMMAND CREATED STATUS \u00a0\u00a0\u00a0\u00a0PORTS \u00a0\u00a0\u00a0\u00a0NAMES \r\n6c70b48aef18 wordpress \"docker-entrypoint.s About an hour ago Up About an hour\u00a0\u00a0\u00a0\u00a00.0.0.0:9083->80\/tcp\u00a0\u00a0\u00a0\u00a0blog \r\n902871f958c1 mysql:latest \"docker-entrypoint.s 2 days ago Up 34 hours \u00a0\u00a03306\/tcp mysql-instance<\/pre>\nBoth of them are running ! To finish the migration, I just have to take care about mysql datas from my old instance to my new one.<\/p>\n
Migrating data from mysql<\/h2>\n
Before initiating the migration, I updated wordpress to the last version, same version deployed using Docker, so I was sure that the mysql tables will be identical. To export datas from my old mysql instance, I just used the mysqldump command :<\/p>\n
mysqldump --single-transaction -h localhost -u root -p wordpress > wordpress-dbbackup_20180203.bak<\/pre>\nI have my backup, all I have to do is to inject it to my new instance :<\/p>\n
mysql -p -h localhost mysql-instance < wordpress-dbbackup_20180203.bak<\/pre>\nAll my datas are up-to-date, accessing my web site on my new server adress giving me all my post and wordpress apparence, all is OK !<\/p>\n","protected":false},"excerpt":{"rendered":"
Few days ago, I changed my personal server, with all my data, to another one. On this new one, I choose to use Docker to deploy all my old stuff, including this web site. When investigating throught Docker, I thought … Continue reading