Docker

Use an SSH tunnel ending at the host also within a Docker container

There are many use cases for SSH tunnels as they allow accessing resources behind firewalls and other obstacles over a secure channel. Since more and more services are containerized, it makes sense to use SSH tunnels also within the context of containers, especially for testing. Using SSH tunnels within Docker containers would require installing an SSH client and mounting keys. In many cases this is not possible without building a new Docker image which includes the client.

Lightning fast integration tests with Docker, MySQL and tmpfs

Integration tests that involve database operations requite to tear down and re-initialize a database multiple times. Although most developer machines offer SSD and enough RAM, database initialization can consume a considerable amount of time nevertheless. Docker allows defining volumes that are mounted directly into the memory by using tmpfs. We can utilize this feature to utilize the speed up disk operations as during database imports, by moving the data from the disk into the memory.

Jupyter docker stacks with a custom user

Jupyter allows to set a custom user instead of**_jovyan_** which is the default for all containers of the [Jupyter Docker Stack][1]. You need to change this user or its UID and GID in order to get the permissions right when you mount a volume from the host into the Jupyter container. The following steps are required: Create an unprivileged user and an asociated group on the host. Here we call the user and the group docker_worker Add your host user to the group.

Verifying Replication Consistency with Percona’s pt-table-checksum

Replication is an important concept for improving database performance and security. In this blog post, I would like to demonstrate how the consistency between a MySQL master and a slave can be verified. We will create two Docker containers, one for the master one for the slave. Installing the Percona Toolkit The Percona Toolkit is a collection of useful utilities, which can be obained for free from the company’s portal. The following commands install the prerequisits, download the package and eventually the package.

Persistent Data in a MySQL Docker Container

Running MySQL in Docker In a recent article on Docker in this blog, we presented some basics for dealing with data in containers. This article will present another popular application for Docker: MySQL containers. Running MySQL instances in Docker allows isolating database infrastructure with ease. Connecting to the Standard MySQL Container The description of the MySQL docker image provides a lot of useful information how to launch and connect to a MySQL container.

Persistent Docker Containers

Docker Fundamentals Docker has become a very popular tool for orchestrating services. Docker it much more lightweight than virtual machines. For instance do containers not require a boot process. Docker follows the philosophy that one container serves only one process. So in contrast to virtual machines which often bundle several services together, Docker is built for running single services per container. If you come from the world of virtualised machines, Docker can be a bit confusing in the beginning, because it uses its own terminology.