Issue with Docker build for Elastalert

General Discussions
1

Installed the Docker Engine on our CentOS VM. I then created the Docker container for our Elastalert.

When running this command:

docker build . -t elastalert2

I was receiving this error:

unable to prepare context: unable to evaluate symlinks in Dockerfile path: lstat /usr/share/man/man5/Dockerfile: no such file or directory

I then navigated to /usr/share/man/man5 but could not find the Dockerfile. Instead I found Dockerfile.5.gz which I extracted for the Dockerfile.5 file.

However when running the

docker build . -t elastalert2

command again I was receiving the same error. I then renamed the Dockerfile.5 file to Dockerfile and was now receiving a new error, this being:

Sending build context to Docker daemon 1.223MB
Error response from daemon: dockerfile parse error line 1: unknown instruction: .NH

.nh is present at the top of the Dockerfile

2

That is not a Dockerfile. Thatā€™s a manual for Dockerfile so you could run man Dockerfile on Linux to get some documentation.

When you got the error message, exactly which directory were you on the filesystem? I guess it was /usr/share/man/man5 because this is the case when you get the exact same error message that you quoted. Docker simply could not find any ā€œDockerfileā€

1 Like
4

So apparently I have no Dockerfile. Other than the Dockerfile manual file, running the command

whereis Dockerfile

comes up with nothing else.

So what do I do?

5

Please, read the documentation before you rely on a command :slight_smile:

whereis is not for searching for files on the filesystem.

whereis --help

Locate the binary, source, and manual-page files for a command.

Dockerfile is not a command

We canā€™t find the Dockerfile for you. And I am not sure you need one. You started this topic with this

If you want to create a container (which you havenā€™t done yet apparently) you donā€™t need to build a docker image. Just follow the instructions in the Elastalert documentation/description

1 Like
6

Thank you for the clarification! I just created my container with this command given in the Elastalert documentation:

docker run -d -v /tmp/elastalert.yaml:/opt/elastalert/config.yaml ghcr.io/jertel/elastalert2/elastalert2

Which created this container:

d2c6f331b82481828f7daa9d12a4fab6132dc58a23675f2ef6eb460311baa2e9

I am currently in this directory:

/var/lib/docker/containers/d2c6f331b82481828f7daa9d12a4fab6132dc58a23675f2ef6eb460311baa2e9

But Iā€™m confused on what to do nextā€¦

Also it says:

ā€œA properly configured config.yaml file must be mounted into the container during startup of the container.ā€

Do I put that config.yaml (which will be called /tmp/elastalert.yaml) into the actual container directory (/var/lib/docker/containers/d2c6f331b82481828f7daa9d12a4fab6132dc58a23675f2ef6eb460311baa2e9), or do I put it into /tmp ?

I am currently running that command without a config.

7

How did you end up in that directory? You make a habit of playing with system folders. Donā€™t go there! because you could brake your container or even the entire Docker service.

Use docker exec if you want to enter a container. I can see you have a problem with the basics. Try this tutorial: Overview of the get started guide | Docker Docs and start with some simple application before elastalert.

8

So how do I use docker exec to run Elastalert commands (such as elastalert-create-index) in the container that I created via the docker run command?

9

Please, read the documentation for that. Everything you need to know is in that. If you donā€™t understand the documentation after trying for some time, share how you tried and we can tell you what your mistake was.