Oracle linux docker image

Docker : Oracle Database on Docker

This article describes a simple build for running an Oracle database on Docker.

Assumptions

This article assumes the following.

• You already have a suitable installation of the Docker Engine. Oracle products are supported on Docker if the host OS is Oracle Linux 7, but you don’t need to use an OL7 host for this to work. You can see how to install Docker on OL7 here.
• You have a basic understanding of Docker and Dockerfiles. You can read an introduction to Docker here, and some basics about writing Dockerfiles here.
• You understand this is an example of a Dockerfile to build an image to run an Oracle database. It’s not meant to be a definitive or supported build. If you want something more generic, you might was to check out the builds and images from Oracle here.

Build the Image

The Dockerfile and scripts this article is based upon can be found here. The build expects the following file system. You will have to download the Oracle 19c database and APEX software yourself and place it in the «software» directory.

$ tree . ├── Dockerfile ├── README.md ├── scripts │ ├── healthcheck.sh │ └── start.sh └── software ├── apex_20.2_en.zip ├── LINUX.X64_193000_db_home.zip └── put_software_here.txt $

The Dockerfile contains some basic instructions, which will be described further here.

With all the files in place you can build the image using the following command.

$ #Docker $ docker build -t ol7_19:latest . $ #Podman $ docker build --format docker -t ol7_19:latest .

The build performs the following actions.

• The build starts by defining some environment variables. The first section contains fixed environment variables. If you want to alter any paths or software versions they need to be reflected here. The PATH environment variable is set based on the value of the ORACLE_HOME environment variable. The next section defines those environment variables that can be set at runtime to alter the database running in a container.
• The software and scripts are copied to the correct locations in the image, «/u01/software» and «/u01/scripts» respectively.
• The first RUN operation creates the «oinstall» group and «oracle» user, installs the prerequisite software and creates the required directories with the correct permissions.
• After switching to the «oracle» user the database software is unzipped, the original media deleted to save space in the image, and a silent software-only installation of the database is performed.
• The default APEX software under the ORACLE_HOME is removed and replaced by the version copied to the «/u01/software» directory.
• After switching to the «root» user the «orainstRoot.sh» and «root.sh» scripts are run to complete the Oracle software-only installation.
• After switching to the «oracle» user, we mark «/u02» as a volume, expose the ports to allow external connections to the database, and reference the «healthcheck.sh» and «start.sh» scripts for use when a container is run based on this image.

You will notice the build phase doesn’t create a database. That is done on the first run of a container.

Run a Container

The database is created the first time the container is started, which means it can take some time for the container to be fully operational, especially because we are also doing an APEX installation into the database.

The simplest way to run a container based on this image is to accept all the defaults and run the following command. It gives the container a name (ol7_19_con), binds a host port to the exposed container port.

$ docker run -dit --name ol7_19_con \ -p 1521:1521 \ --shm-size="1G" \ ol7_19:latest

In the previous example the storage is not persistent, so if the container were removed the database files would be lost. We can solve this problem by creating a directory on the host file system and mounting it to «/u02» in the container. Now the data files reside outside the container. See the Persistent Storage section about the setup of the host volume.

$ mkdir -p ~/volumes/ol7_19_con_u02/ $ docker run -dit --name ol7_19_con \ -p 1521:1521 \ --shm-size="1G" \ -v /u01/volumes/ol7_19_con_u02/:/u02 \ ol7_19:latest

We could have used a managed volume or a data volume container instead. These approaches are described here.

In the previous examples we’ve exposed the database to the outside world, but if we want other containers to speak directly to it, we must create a Docker network and associate the container with that network.

$ docker network create my_network $ docker run -dit --name ol7_19_con \ -p 1521:1521 -p 5500:5500 \ --shm-size="1G" \ --network=my_network \ -v /u01/volumes/ol7_19_con_u02/:/u02 \ ol7_19:latest

So far we have relied on the default settings for the database creation, but we can influence this by setting the appropriate environment variables in the run command.

$ docker run -dit --name ol7_19_con \ -p 1521:1521 -p 5500:5500 \ --shm-size="1G" \ -v /u01/volumes/ol7_19_con_u02/:/u02 \ -e "ORACLE_SID=cdb2" \ -e "SYS_PASSWORD=SysPassword2" \ -e "PDB_NAME=pdb2" \ -e "PDB_PASSWORD=PdbPassword2" \ -e "APEX_EMAIL=me2@example.com" \ -e "APEX_PASSWORD=ApexPassword2" \ ol7_19:latest

Persistent Storage

If you are using an external host volume for persistent storage, the build expects it to owned by a group with the group ID of 1042. This is described here.

start.sh Script

The start.sh script is responsible for creating the database on the first run of the container. It performs the following actions.

• Defines the «gracefulshutdown» function to turn off the database and associates it with the SIGINT , SIGTERM and SIGKILL traps.
• Defines the «fixConfig» function to create symbolic links to important config files from persistent storage. This will become obvious later.
• Check if the database already exists under the «/u02/oradata» location. If not, create the database.
• Start the listener.
• Use the DBCA to silently create a database.
• Turn on Oracle Managed Files (OMF) and make sure the PDB automatically starts on restart.
• Copy some important config files to the «/u02/config» directory and run the «fixConfig» function to create symbolic links to the new locations where possible. The «/etc/oratab» file must be copied, not linked.
• Perform a silent installation of APEX
• If the database was already present, it means this could be a new run of the base image, pointing at a persistent volume already containing the database. In this case, run the «fixConfig» function to recreate the symbolic links and copy back the «/etc/oratab» file, then start the database.
• Tails the alert log as a background process and waits on the resulting process ID. If this tail ends the container will be turned off.

healthcheck.sh Script

The healthcheck.sh script is really simple. It connects to the database and runs a query. If the query is successful it returns «0», otherwise it returns «1».

Managing the Container

Once the container is running you can connect to a bash shell using the following command.

$ docker exec -it ol7_19_con bash

The container can be stopped and started using the following commands. The «—time» parameter give the database a chance to shutdown gracefully. Restarting the container has no impact on ephemeral storage, so no data will be lost, even if you are not using persistent storage.

$ docker stop --time=30 ol7_19_con $ docker start ol7_19_con

The following command removes the container and the associated volumes. If you are not using persistent storage this will result in the loss of the database files.

Hope this helps. Regards Tim.

Created: 2017-12-10 Updated: 2021-06-14

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Oracle Linux container images

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oracle/container-images

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README.md

This repo stores the architecture-specific rootfs tarballs for the official Oracle Linux base images published on Docker Hub and GitHub Container Registry.

Oracle Linux is an open-source operating system available under the GNU General Public License (GPLv2). Suitable for general purpose or Oracle workloads, it benefits from rigorous testing of more than 128,000 hours per day with real-world workloads and includes unique innovations such as Ksplice for zero-downtime kernel patching, DTrace for real-time diagnostics, the powerful Btrfs file system, and more.

The Oracle Linux images are intended for use in the FROM field of a downstream Dockerfile . For example, to use the latest optimized Oracle Linux 7 image, specify FROM oraclelinux:7-slim .

Due to the fact that only the latest tarball for each tag is stored in the dist-amd64 and dist-arm64v8 branches, it is not possible to use Git’s history to determine what has changed and when. Thus, we maintain a CHANGELOG in the master branch that documents the changes made to various images by date.

Differences between oraclelinux:7 and oraclelinux:7-slim

Oracle recommends using oraclelinux:7-slim as your base layer as it contains just enough packages for yum to work to install more packages. Therefore, it has the smallest size and the least amount of unneeded content.

The oraclelinux:7 images is based off the package set what would be installed via a Minimal install of Oracle Linux.

Differences between oraclelinux:8 and oraclelinux:8-slim

As with Oracle Linux 7, the 8-slim variant contains just enough packages to install more.

However, it also replaces the standard dnf client with the tiny microdnf tool to further reduce space. If you need the functionality of the full client, you can install it via RUN microdnf install dnf in your downstream Dockerfile .

To provide yum compatibility, use RUN microdnf install yum .

Using modules with microdnf

An example of how to enable module support when using microdnf can be seen in the oraclelinux:8 variants of the OracleLinuxDeveloper images in the Oracle Docker Images repo.

Finding container images of Oracle products

We provide sample Dockerfiles for several Oracle products in the Oracle Docker Images repository on GitHub. Many of these images are also available for direct download from the Oracle Container Registry.

Oracle Linux is released under the GPLv2. See the LICENSE file in this repository for more information.

Oracle provides support to Oracle Linux subscription customers via the My Oracle Support portal. The Oracle Linux Docker images are covered by Oracle Linux Basic and Premier support subscriptions. Customers should follow existing support procedures to obtain support for Oracle Linux running in a Docker container.

For users without an Oracle Linux support subscription, the following resources are available:

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