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- Overview
- Database and Docker: the question of persistence
- Step-by-step setup
- 1. Install Docker
- 2. Temporarily disable the firewall
- 3. Create a local volume (directory on the host)
- 4. Create and execute HFSQL container
- 5. Re-enable the firewall (firewalld)
- 6. Query the daemon docker
- Access to the HFSQL server of the container
HFSQL and Docker
 Available only with this kind of connection
Docker is a software platform that allows you to run applications in software containers on Linux (Docker runs like a daemon). Each software container will have its own environment, which simplifies testing and deployment. The advantage of containers over virtualization is that some parts access the "host" server directly (whereas virtualization creates a "complete" layer of abstraction). There are many additional tools that complement Docker to manage redundancy, scalability, etc. As part of the development of an application, Docker makes it possible to isolate each module (the database, the Web server dedicated to web services and the Web server dedicated to sites). These different modules can thus be run on the same server while being isolated from each other. It is also possible to test a container and then implement it under identical conditions. Notes: - Docker is also available for Windows.
- This purpose of this help page is not to explain how Docker works. However, to use the Docker container that contains the HFSQL server, it is necessary to be familiar with Docker and, in particular:
- know how to install a new container from the Docker image of the HFSQL server,
- know how to manage at least one volume required for data persistence,
- know how to manage the network configuration inside Docker.
- Only the 64-bit version is available.
Database and Docker: the question of persistence In its early days, Docker was designed to run "stateless" applications, i.e. without persistent data (data is only temporary and deleted when the container stops). This operating mode would not be very useful for a database. Since then, Docker has evolved and allows the use of data volumes that are associated with a container (Docker Volume). The data can then be: - in a local volume at the Docker host,
- in a volume on SAN/NAS.
Therefore, it is possible to use an HFSQL database in a Docker container while respecting this division. This keeps the advantage of being able to change the HFSQL container (update, etc.) while keeping the data. Note: in the following paragraphs, the command lines illustrating operations under Linux can be used under Ubuntu. 1. Install Docker First and easiest step: installing Docker on the host server. sudo apt install docker.io The application name is "docker.io", not "docker". 2. Temporarily disable the firewall The corresponding statements are: sudo systemctl stop firewalld
sudo systemctl disable firewalld
sudo reboot Note: This temporary deactivation may be necessary to avoid an error when launching the Docker container (error: "Error response from daemon: driver failed programming external connectivity on endpoint HFSQL_DOCKER"). 3. Create a local volume (directory on the host) In order for the data in the database files to be persistent (you want to keep them), it is preferable not to store these files in the container. To do this, a folder is created (or a mount for a SAN/NAS) on the host. In the example below, the folder is created directly on the host's storage. sudo mkdir /home/docker
sudo mkdir /home/docker/bdd_hfsql
sudo chmod -R 777 /home/docker ImportantIn this command line example, all rights are given to the directory. It is strongly recommended to restrict the rights of the user running the daemon docker as much as possible. 4. Create and execute HFSQL container At this stage, the daemon docker is installed and the storage volume is created but HFSQL has not yet been installed. It's actually Docker that will "install" it from its online repository: all you have to do is tell Docker which version you want to install (all available versions can be found in the "Build Details" tab of the "windev/hfsql" repository on "hub.docker.com". 4.a. Setup "for test" For testing purposes, it is possible to use the "create" and "start" commands (the command line below has line breaks for more readability). sudo docker create
--name HFSQL_DOCKER
--volume /home/docker/bdd_hfsql
:/var/lib/hfsql
--publish 4923:4900
windev/hfsql:US230053b Here are the parameters of the command above: - "name": indicates the name of the container.
- "volume": indicates the "binding" between the volume and the directory defined in the container. In the HFSQL server configuration, the database path will be seen as "var/lib/hfsql".
- "publish": indicates the container access port (4923 in this example) and the redirection to the port inside the container (4900: the standard HFSQL port).
- the name of the docker package and the HFSQL version (US230053b" in this example).
This command line will cause HFSQL Docker to download the first time. The following information will be displayed in the console (the version number may change): Unable to find image
"windev/hfsql:US230053b" locally
FR230053b: Pulling from windev/hfsql
... Then, simply start the execution of the container by the command "start": sudo docker start HFSQL_DOCKER 4.b. Setup "for production" For a "real" setup, it is necessary to use the Docker "run" command. sudo docker run -dit
--restart unless-stopped
--name HFSQL_DOCKER
--volume /home/docker/bdd_hfsql
:/var/lib/hfsql
--publish 4923:4900
windev/hfsql:US230053b In this command line, the parameters are identical to those of the "create" command, plus the restart command. Tip The following command launches Docker when the machine boots: sudo systemctl enable docker Some notes on the installation: - the port provided to the container must be free on the host.
- the host directory (e.g. "/home/bob/bdd") must exist and have the necessary permissions.
- if the server must be accessible from outside the host, the port must be authorized by the host's firewall.
- only versions validated by our quality department are published on the Docker repository after specific tests. There are no pre-release versions or similar.
Environment variables: When the container is created, if the databases do not exist, it is possible to define environment variables, for example, via the syntax:
-e HFSQL_RANDOM_PASSWORD=yes You can use one of the following three variables (or nothing for the default "admin" mode): - HFSQL_PASSWORD: Initial account password.
- HFSQL_PASSWORD_FILE: path to the file containing the initial account password.
- HFSQL_RANDOM_PASSWORD: The initial account password is randomly generated.. It is displayed on the standard output and can be found in the logs with the command:
You can also use the following variable (optional): HFSQL_USER: Account name (admin by default). 5. Re-enable the firewall (firewalld) Of course, once the setup is finished, the firewall must be re-enabled if it was disabled in step 2. sudo systemctl enable firewalld
sudo systemctl start firewalld 6. Query the daemon docker It is possible to view containers being executed, stop a container, etc.. thanks to the "docker container" command. For example, to list containers being executed: Access to the HFSQL server of the container As soon as the container is running, it is possible to access the HFSQL server by indicating: - the name of the host server for the server,
- the port associated with the container as the port for HFSQL (in this article: 4923),
- the default HFSQL user and password (don't forget to change them).
Note: remember to check that the databases you've created are actually in the intended volume and not in the container, so as not to lose them in the event of container shutdown or restart. A Docker container is installed via a "repository": so don't Seek in the WINDEV directory to find the installation.. The HFSQL Docker container is available at this address: " https://hub.docker.com/r/windev/hfsql/".
This page is also available for…
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