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Category: Containers

Storing Credentials For Containers

Published 2018-01-18 by Kevin Feasel

Andrew Pruski shows how to store a credential using Powershell and pass it into a Docker container:

I work with SQL Server in containers pretty much exclusively when testing code and one of my real bug bears is that SQL Server in containers does not support Windows authentication (unless you’re using Windocks).

So when I’m working I find it quite annoying to have to specify a SA username & password when I want to connect.

OK, I can use Get-Credential, assign to a variable, and then reference that in a connection string but I want something a bit more permanent especially as I always use the same password for all my containers

Read on for Andrew’s method, and check out Rob Sewell’s method in the comments.

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Protecting Sensitive Data In Docker

Published 2017-12-12 by Kevin Feasel

Jatin Demla shows how to create Docker secrets:

Managing the password, access tokens and private keys are being tedious in the application. Any small mistakes accidentally expose all the secret information. Even storing such thing in docker images can be easily accessible one should just run the image in the interactive mode container and all your application code is available in containers. Docker provides secrets to protect all secret data.

This blog explains the low-level of storage information as well as secured access to docker secret. so, let’s get started.

Read the whole thing, especially if you’ve gone container-happy.

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Spinning Up SQL Server Containers In Jenkins

Published 2017-12-05 by Kevin Feasel

Chris Adkin has a few tips for loading SQL Server in Jenkins as part of testing or deployment:

Problem 1 Image Tag

There is no image tag specified for the microsoft/mssql-server-linux image, therefore, if Microsoft push a newer version of the image to docker hub, this will be pulled down from docker hub when the build pipeline runs. This is easily fixed by tagging the image with a tag for an explicit version, e.g. microsoft/mssql-server-linux:2017-GA.

Click through for the starting code, two additional issues, and the corrected code.

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Docker And R

Published 2017-11-21 by Kevin Feasel

Mara Averick has some resources to help you get started with running R in a Docker container:

liftr 📦 by Nan Xiao

liftr aims to solve the problem of persistent reproducible reporting. To achieve this goal, it extends the R Markdown metadata format, and uses Docker to containerize and render R Markdown documents.

Click through for those resources as well as an addictive 8-bit animated GIF.

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SQL On Docker And Running SQL Queries

Published 2017-11-09 by Kevin Feasel

Rob Sewell loads SQL on Windows & Linux via Docker and shows how to run a query against it using Powershell:

In only a few seconds you have a SQL 2017 instance up and running (Take a look at Andrews blog at dbafromthecold.com for a great container series with much greater detail)

Now that we have our container we need to connect to it. We need to gather the IPAddress. We can do this using docker command docker inspect but I like to make things a little more programmatical. This works for my Windows 10 machine for Windows SQL Containers. There are some errors with other machines it appears but there is an alternative below

Read the whole thing.

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SQL Server Agent On A Linux Container

Published 2017-10-26 by Kevin Feasel

Andrew Pruski shows how to get the SQL Agent service running on a Linux container:

Now, one of the benefits of attending SQL Saturdays is that you get to pick the brains of a lot of very clever people and luckily for me, Jan Van Humbeek (blog|twitter) was there.

Jan said that he had gotten the SQL Agent running in Linux containers so I asked if he could send on his code and he very kindly obliged.

So, the disclaimer for this blog post is that I didn’t write the code here, Jan did. All I’ve done is drop it into a dockerfile so that an image can be built. Thank you very much Jan!

Click through for Jan’s code and Andrew’s presentation of the process.

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Reasons For Using Docker With R

Published 2017-10-17 by Kevin Feasel

Jeroen Ooms gives us a few reasons why we might want to containerize our R-based products:

The flagship of the OpenCPU system is the OpenCPU server: a mature and powerful Linux stack for embedding R in systems and applications. Because OpenCPU is completely open source we can build and ship on DockerHub. A ready-to-go linux server with both OpenCPU and RStudio can be started using the following (use port 8004 or 80):

docker run -t -p 8004:8004 opencpu/rstudio

Now simply open http://localhost:8004/ocpu/ and http://localhost:8004/rstudio/ in your browser! Login via rstudio with user: opencpu (passwd: opencpu) to build or install apps. See the readme for more info.

This is in the context of one particular product, but the reasons fit other scenarios too.  H/T R-Bloggers

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New Docker Tag For SQL Server 2017

Published 2017-10-05 by Kevin Feasel

Hamish Watson notes that there are new Docker tags for SQL Server 2017:

I have been using SQL Server 2017 running on Linux for a while now (blog post pending) and use the official images from:

https://hub.docker.com/r/microsoft/mssql-server-linux/

To get the latest I used to run

docker pull microsoft/mssql-server-linux:latest

However today I noticed that the :latest tag had been removed:

Click through to see the tag you probably want to use.

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Limiting Docker Container Resources

Published 2017-10-04 by Kevin Feasel

Andrew Pruski shows how to cap the resources available to a container:

What I’ve done here is use the cpus and memory switches to limit that container to a maximum of 2 CPUs and 2GB of RAM. There are other options available, more info is available here.

Simple, eh? But it does show something interesting.

I’m running Docker on my Windows 10 machine, using Linux containers. The way this works is by spinning up a Hyper-V Linux VM to run the containers (you can read more about this here).

Read on to learn more.

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Docker Stop Versus Docker Kill

Published 2017-10-02 by Kevin Feasel

Andrew Pruski explains why docker kill is so much faster than docker stop:

When running demos and experimenting with containers I always clear down my environment. It’s good practice to leave a clean environment once you’ve finished working.

To do this I blow all my containers away, usually by running the docker stop command.

But there’s a quicker way to stop containers, the docker kill command.

Sending SIGTERM isn’t particularly polite and doesn’t let processes clean up, which could leave your process in an undesirable state during future runs.  But if you’re just re-deploying a container, you don’t really care about the prior state of the now-disposed container.

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