Ansible installation of MongoDB - missing mongodb folder in /var/run

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1

Hi,

I’m deploying MongoDB to a number of servers using the script below. Servers are Ubuntu 18.0.4. I have an issue where the installation fails to create a mongo folder in /var/run/ and thus can’t start the service (No place to put the PID file)
I modified the Ansible script to create the /var/run/mongodb folder with the correct permissions, so this installs MongoDB and starts it, but after a reboot the MongoDB folder is removed (because var/run is not persistent)

Is this an issue with how I’m installing mongo via Ansible?

  • hosts: mongo
    become: true
    gather_facts: true
    vars:
    ################# Mongo #################
    mongodb_db_path: ‘/data/db’
    mongodb_log_path: ‘/data/log’

tasks:

2

Hi,

I'm deploying MongoDB to a number of servers using the script below. Servers are Ubuntu 18.0.4. I have an issue where
the installation fails to create a mongo folder in /var/run/ and thus can't start the service (No place to put the PID file)
I modified the Ansible script to create the /var/run/mongodb folder with the correct permissions, so this installs
MongoDB and starts it, but after a reboot the MongoDB folder is removed (because var/run is not persistent)

Is this an issue with how I'm installing mongo via Ansible?

Hello Stephen,

I would expect that the package installed via APT takes care of the PID file and /run subdirectory management.

Regards
         Racke

- hosts: mongo
become: true
gather_facts: true
vars:
################# Mongo #################
mongodb_db_path: '/data/db'
mongodb_log_path: '/data/log'

tasks:

################################################################
# Install/Setup Mongo
################################################################
- name: Add MongoDB public GPG key to the apt repo
apt_key:
url: '{{ mongo_key_url }}'
state: present

- name: Add MongoDB Repo
apt_repository:
repo: '{{ mongo_repo_url }}'
state: present

- name: Run the equivalent of "apt-get update" as a separate step
apt:
update_cache: yes

- name: Install MongoDB
apt:
name: 'mongodb-org'
state: latest

## Fix
- name: Create diretory for pid

-> file:

3

Hi,

I'm deploying MongoDB to a number of servers using the script below.
Servers are Ubuntu 18.0.4. I have an issue where the installation fails
to create a mongo folder in /var/run/ and thus can't start the service (No
place to put the PID file) ... but after a reboot the MongoDB folder is
removed (because var/run is not persistent)
[...]
Is this an issue with how I'm installing mongo via Ansible?

No. It's not Ansible issue at all. MongoDB doesn't care about the directory.
There are more options:

1) Put "pidfile" to persistent location
   https://docs.mongodb.com/manual/reference/configuration-options/

2) Fix the service to create the directory. See hints
   https://github.com/mongodb/mongo/commit/50ca596ace0b1390482408f1b19ffb1f9170cab6

3) Create the directory on your own at startup.

Cheers,

  -vlado

4

Hi Vladimir,

If I install Mongo manually apt-get install mongodb-org if install fine and the /var/run/mongodb folder is created every reboot
it’s only when I install via Ansible then it doesn’t.

e.g. a manual install also creates a mongodb file in /etc/init.d the Ansible install does not

I have worked round the problem with your option 3.
I have created a file in /urs/lib/tmpfiles.d called mongo.conf contents of:

d /var/run/mongodb 0755 mongodb mongodb -

This creates the mongodb directory every reboot.

It does seem weird that the installs differs via Ansible vs manual

Regards,
Steve

5

Hi Vladimir,

If I install Mongo manually apt-get install mongodb-org if install fine and the /var/run/mongodb folder is created every reboot
it's only when I install via Ansible then it doesn't.

...

It does seem weird that the installs differs via Ansible vs manual

Yes, I would suggest focussing on fixing that, rather than "working around" it.
There should be no difference between apt-get install package and the
corresponding ansible apt task.

6

Hi Stephen,

> > I'm deploying MongoDB to a number of servers using the script below.
> > Servers are Ubuntu 18.0.4. I have an issue where the installation
> > fails
> > to create a mongo folder in /var/run/ and thus can't start the service
> > (No
> > place to put the PID file) ... but after a reboot the MongoDB folder is
> > removed (because var/run is not persistent)
> > [...]
> > Is this an issue with how I'm installing mongo via Ansible?

> No. It's not Ansible issue at all. MongoDB doesn't care about the
> directory.
> There are more options:
> 1) Put "pidfile" to persistent location
> https://docs.mongodb.com/manual/reference/configuration-options/
> 2) Fix the service to create the directory. See hints
> https://github.com/mongodb/mongo/commit/50ca596ace0b1390482408f1b19ffb1f9170cab6
> 3) Create the directory on your own at startup.

If I install Mongo manually apt-get install mongodb-org if install fine
and the /var/run/mongodb folder is created every reboot
it's only when I install via Ansible then it doesn't.

e.g. a manual install also creates a mongodb file in /etc/init.d the
Ansible install does not

I have worked round the problem with your option 3.
I have created a file in /urs/lib/tmpfiles.d called mongo.conf contents of:

d /var/run/mongodb 0755 mongodb mongodb -

This creates the mongodb directory every reboot.

It does seem weird that the installs differs via Ansible vs manual

There shouldn't be any difference in installing packages manually and with
Ansible. If you're sure you've found a difference open an issue with the
Ansible module.

OFF-TOPIC: MongoDB. Just to close this issue here.

You've configured the repo and installed "mongodb-org" which is maintained
and supported by MongoDB Inc (they claim it's for Ubuntu). Standard Ubuntu
18.04 does not include it.

If you want to find the problem take a look what packages are installed

    dpkg -l | grep mongo

See what files are installed by the package

     apt-file list mongodb-org

Examine the files and see what services are active

    /etc/init.d/mongodb
    /etc/mongodb.conf
    /lib/systemd/system/mongodb.service

FWIW. Standard Ubuntu 18.04 mongodb-server put PID by default into the file

    /var/lib/mongodb/mongod.lock

and the directory /var/run/mongodb lists the socket

    $ ls -1 /var/run/mongodb/
    mongodb-27017.sock

init.d shows

    $ grep RUNDIR /etc/init.d/mongodb
    RUNDIR=/run/mongodb
    PIDFILE=$RUNDIR/$NAME.pid
    DAEMON_OPTS=${DAEMON_OPTS:-"--unixSocketPrefix=$RUNDIR --config $CONF
    run"} test -e "$RUNDIR" || install -m 755 -o mongodb -g mongodb -d
            "$RUNDIR"

If you think it's MongoDB problem proceed there.

HTH, Cheers,

  -vlado