Introducing cf-remote: Tooling to deploy CFEngine
Posted by: Ole Herman Elgesem
About a year ago, I wrote a small python script to automate installing and bootstrapping CFEngine on virtual machines in AWS. It had some hard coded IP addresses that I needed to update when I spawned new hosts, but other than that, it worked well. During manual testing, it saved me a lot of time instead of having to do things manually.
Deploying CFEngine normally consists of these steps:
- Determine what CFEngine package to use.
- Download appropriate package if you haven’t already –
- Copy the package to the host –
- Log into the host –
- Install the package –
- Bootstrap CFEngine –
At a company hackathon I decided to make my script into something better, something that would be useful to my colleagues, and maybe even CFEngine users in general. Enter
cf-remote can be used to show information about a system before installing CFEngine. The
info command logs into the system, runs a few commands and parses
/etc/os-release to present relevant information:
$ cf-remote info -H 22.214.171.124 email@example.com OS : rhel (fedora) Architecture : x86_64 CFEngine : Not installed Policy server : None Binaries : rpm, yum
cf-remote command line tool is written in Python, and uses Fabric to log into the system via SSH. (Add
--log-level debug to see all commands
cf-remote runs). Note that there are almost no dependencies on the target system. You only need ssh access and a shell which can perform basic UNIX commands like
The printout shows that it’s a Red Hat machine, and CFEngine is not installed yet.
Install and bootstrap
cf-remote can install CFEngine on the system above. The only thing you really need to specify is IP address(es):
$ cf-remote install --hub 126.96.36.199 --bootstrap 172.31.30.237
Here is the output from the example above:
$ cf-remote install --hub 188.8.131.52 --bootstrap 172.31.30.237 firstname.lastname@example.org OS : rhel (fedora) Architecture : x86_64 CFEngine : Not installed Policy server : None Binaries : rpm, yum Package already downloaded: '/Users/olehermanse/.cfengine/cf-remote/packages/cfengine-nova-hub-3.12.1-1.x86_64.rpm' Copying: '/Users/olehermanse/.cfengine/cf-remote/packages/cfengine-nova-hub-3.12.1-1.x86_64.rpm' to '184.108.40.206' Installing: 'cfengine-nova-hub-3.12.1-1.x86_64.rpm' on '220.127.116.11' CFEngine 3.12.1 was successfully installed on '18.104.22.168' Bootstrapping: '22.214.171.124' -> '172.31.30.237' Bootstrap successful: '126.96.36.199' -> '172.31.30.237'
We can guess the username and CFEngine version if not specified. Many hosts can be specified in a single command:
$ cf-remote install --hub 188.8.131.52 --bootstrap 172.31.30.237 --clients 184.108.40.206,220.127.116.11,18.104.22.168
Or using a newline delimited file:
$ cat ./clients 22.214.171.124 126.96.36.199 188.8.131.52 $ cf-remote install --hub 184.108.40.206 --bootstrap 172.31.30.237 --clients ./clients
Other useful commands
The tooling includes a few other useful utilities. Some of these things can be done in CFEngine policy, but
cf-remote doesn’t assume that CFEngine is installed. Thus, these commands can be useful both before and after installing CFEngine.
scp command can be used to transfer files to the host.
$ echo "Hello, world" > txt $ cf-remote -H 220.127.116.11 scp txt Copying: 'txt' to '18.104.22.168'
The destination defaults to the home folder of the SSH user (
/home/ec2-user/txt in this example). The command doesn’t actually use an
scp executable, but Fabric’s
Arbitrary command execution
We can also run commands as if we were logged in via ssh:
$ cf-remote -H 22.214.171.124 run "cat txt" 126.96.36.199: 'cat txt' -> 'Hello, world'
This is especially useful to run commands on many hosts.
-H accepts a comma separated list or a path to a file (beginning with
We also made some videos showing how to install and use
The tool is completely open source, and part of the CFEngine core repository:
The README has installation instructions. It should work on any system with curl, Python(3), Fabric, and Requests. We’ve tested it on Linux(Fedora) and OS X. Currently, RHEL and Ubuntu targets are supported. Debian, Fedora, and CentOS should also work as they use
rpm. The target must be running an SSH server with your key in
authorized_keys, so Fabric can log in.
Anyone can contribute to
cf-remote, we have a curated list of tickets to pick up here:
Additional platform support (beyond dpkg and rpm) and parallellized installation are good next features.