RANCID in Docker and Kubernetes

This is a Docker container to run the RANCID software, which periodically collects Cisco router and switch configurations and uploads them into a source control repository.

All three version control systems supported by RANCID (CVS, SVN, and GIT) are installed within this image, and can be used by setting up RANCID appropriately.

This image also contains ssmtp, the extremely simple MTA.

This project is designed to be used as a Kubernetes Deployment. Usage as a Kubernetes CronJob would be preferred, but cannot work due to a technical limitation.

Configuration

This container is configured in a non-standard way compared to most Docker environments, but this software was never designed to be cloud-native anyway. We use a single git repository to store all configuration, as well as the router backups.

• Create a private repository on Github.

• Read the Github Deploy Key Documentation.

• Generate an ssh key to be used as a Github deploy key, using this command:

  ssh-keygen -C rancid -f rancid < /dev/null

• Your ssh public key is in rancid.pub. This is the Github deploy key.

• Your ssh private key is in rancid. This is not uploaded to Github.

• Upload the Github deploy key to Github. Select the Allow write access check box.

• Create a local checkout of your Github repository:

  git clone git@github.com:username/repository.git

• Within your local checkout, create this directory structure:

  ├── .cloginrc # <-- this file contains passwords for RANCID ├── .gitignore # <-- ignore any files you want (optional) ├── rancid.conf # <-- main RANCID configuration file ├── README.md # <-- anything you want! (optional) ├── .ssh # <-- ssh configuration directory │   ├── config # <-- ssh configuration file (see example below) │   ├── id_rsa # <-- ssh private key (copy of "rancid" ssh key file) │   └── id_rsa.pub # <-- ssh public key (copy of "rancid.pub" ssh key file) └── ssmtp.conf # <-- ssmtp configuration file (see example)

• Create one directory for each RANCID group, with the contents:

  mkdir $GROUP mkdir $GROUP/configs touch $GROUP/router.db

• Following the RANCID documentation, configure each switch or router in the router.db file.

• Commit everything and push it up to Github.

Example .cloginrc

• Documentation: https://www.shrubbery.net/rancid/man/cloginrc.5.html

The example below shows you how to set up RANCID to fetch data from all switches and routers which have a hostname *.example.com. The username will be myusername. The unprivileged password will be unprivilegedpassword. The privileged password (AKA "enable password") will be privilegedpassword. All devices will be accessed using ssh.

add user *.example.com myusername
add password *.example.com {unprivilegedpassword} {privilegedpassword}
add method *.example.com {ssh}

You should customize this example for your environment.

Example rancid.conf

• Documentation: https://www.shrubbery.net/rancid/man/rancid.conf.5.html

The example below shows you the minimum necessary for this container to work:

TERM=network;export TERM
LC_COLLATE="POSIX"; export LC_COLLATE
uid=`perl -e 'print "$>"'`
test "$uid" -eq 0 && echo "Do not run $0 as root!" && exit 1
umask 027
PERL5LIB="/usr/lib/rancid"; export PERL5LIB
TMPDIR=/tmp; export TMPDIR
BASEDIR=/var/rancid; export BASEDIR
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin; export PATH
SENDMAIL="/usr/sbin/sendmail"
CVSROOT=$BASEDIR/github ; export CVSROOT
LOGDIR=/var/log/rancid; export LOGDIR
RCSSYS=git; export RCSSYS
ACLSORT=YES; export ACLSORT
FILTER_PWDS=NO; export FILTER_PWDS
PAR_COUNT=8; export PAR_COUNT
LIST_OF_GROUPS=""

Be sure and configure your LIST_OF_GROUPS according to the documentation.

Example ssmtp.conf for Google GMail for Business

The example below shows you how to configure ssmtp to work with your Google GMail for Business email account.

TLS_CA_FILE=/etc/pki/tls/certs/ca-bundle.crt
root=your-email@example.com
mailhub=smtp.gmail.com:587
rewriteDomain=example.com
hostname=rancid.example.com
useSTARTTLS=YES
FromLineOverride=YES

AuthUser=your-email@example.com
AuthPass=your-password
AuthMethod=LOGIN

Run this container

This command will run the rancid-run command within the container, then exit. For a production deployment, you should use the included supercronic binary and a crontab of your choosing.

git clone git@github.com:username/repository.git myrepository
docker run --rm -it -v $PWD/myrepository:/var/rancid irasnyd/rancid rancid-run -m "your-email@example.com"

You can adapt this example for use as a Kubernetes Deployment by using the supercronic command to run this command periodically.

Known Bugs / TODO List

Kubernetes CronJob

This project currently runs as a Kubernetes Deployment, using the supercronic utility as a cron command scheduler. This is a workaround for a technical limitation in the Kubernetes CronJob scheduler, which does not yet understand the scheduling limitations of Kubernetes PersistentVolume which are backed by AWS EBS (Elastic Block Store) block devices. Kubernetes sometimes schedules the Pod to a Node in the incorrect AWS Availability Zone (AZ).

The Kubernetes Deployment scheduler is aware of this limitation, and always schedules the Pod correctly.