systemctl not found while building mongo image

Question

I am trying to build a mongo 4.4 image based on the official image Dockerfile but I am running into an issue with systemctl not found. The image itself has a line to remove it after setup, but not sure where it came from. Any ideas?

Setting up mongodb-org-database-tools-extra (4.4.0) ...
Setting up librtmp1:amd64 (2.4+20151223.gitfa8646d.1-1) ...
Setting up libkrb5support0:amd64 (1.16-2ubuntu0.1) ...
Setting up krb5-locales (1.16-2ubuntu0.1) ...
Setting up libkeyutils1:amd64 (1.5.9-9.2ubuntu2) ...
Setting up libk5crypto3:amd64 (1.16-2ubuntu0.1) ...
Setting up libkrb5-3:amd64 (1.16-2ubuntu0.1) ...
Setting up libgssapi-krb5-2:amd64 (1.16-2ubuntu0.1) ...
Setting up libcurl4:amd64 (7.58.0-2ubuntu3.10) ...
Setting up mongodb-database-tools (100.1.1) ...
Setting up mongodb-org-mongos (4.4.0) ...
Setting up mongodb-org-tools (4.4.0) ...
Setting up mongodb-org-server (4.4.0) ...
/var/lib/dpkg/info/mongodb-org-server.postinst: 43: /var/lib/dpkg/info/mongodb-org-server.postinst: systemctl: not found
dpkg: error processing package mongodb-org-server (--configure):
 installed mongodb-org-server package post-installation script subprocess returned error exit status 127
Setting up mongodb-org-shell (4.4.0) ...
dpkg: dependency problems prevent configuration of mongodb-org:
 mongodb-org depends on mongodb-org-server; however:
  Package mongodb-org-server is not configured yet.

dpkg: error processing package mongodb-org (--configure):
 dependency problems - leaving unconfigured
Processing triggers for libc-bin (2.27-3ubuntu1.2) ...
Errors were encountered while processing:
 mongodb-org-server
 mongodb-org
[91mE: Sub-process /usr/bin/dpkg returned an error code (1)
[0mThe command '/bin/sh -c set -x   && export DEBIAN_FRONTEND=noninteractive    && apt-get update   && echo "mongodb-org hold" | dpkg --set-selections  && echo "mongodb-org-server hold" | dpkg --set-selections   && echo "mongodb-org-shell hold" | dpkg --set-selections    && echo "mongodb-org-mongos hold" | dpkg --set-selections   && echo "mongodb-org-tools hold" | dpkg --set-selections    && apt-get install -y       ${MONGO_PACKAGE}=$MONGO_VERSION         ${MONGO_PACKAGE}-server=$MONGO_VERSION      ${MONGO_PACKAGE}-shell=$MONGO_VERSION       ${MONGO_PACKAGE}-mongos=$MONGO_VERSION      ${MONGO_PACKAGE}-tools=$MONGO_VERSION   && rm -f /usr/local/bin/systemctl   && rm -rf /var/lib/apt/lists/*  && rm -rf /var/lib/mongodb  && mv /etc/mongod.conf /etc/mongod.conf.orig' returned a non-zero code: 100

Answer 1

To be precise

RUN ln -s /bin/echo /bin/systemctl
RUN apt-get -qqy install  mongodb-org

Answer 2

FL3SH answer works but to convey the meaning more effectively you can create a symbolic link from /bin/systemctl to /bin/true.

/bin/true is a command wich always return 0 (the truthy value of the shell) so it does not fail. It's a standard way to indicate that you want to return true. See this SO post also

The command you need to add in the Dockerfile is:

RUN ln -s /bin/true /usr/local/bin/systemctl

or

RUN ln -s /bin/true /bin/systemctl

The effect is that you trick the post-install script by calling /bin/true instead of /bin/systemctl

You can find the same trick into the official mongodb Dockerfile 4.4 line 91 that haytham linked in his description.

/bin/echo works as well as /bin/true because echo returns 0 as well. You can try it by doing

echo "test"
echo $?

And you'll see 0 as the result of the second echo.

Answer 3

echo ln to /bin/systemctl solves the issue.