yanghui3j / devnet-1223

Workshop for Cisco Live 2017 - Las Vegas

Cisco Live 2017 - DEVNET-1223

Workshop: Automating IOS-XR with Ansible

The workshop is meant to be a basic introduction to using Ansible with IOS-XR. It includes how to set up IOS-XR to allow Ansible access (primarily to the console/exec CLI), an overview of the existing Ansible iosxr_* modules, and an intro to the possibility of using the YANG Development Kit (YDK) in custom Ansible modules.

Most of the contents of this repo are available via the tithomas1/cl17devnet1223 container on the Docker Hub. To experiment with an actual IOS-XR instance (VM or physical), the inventory in the container is pre-built to include an xr621 host. You can map a target IP for that host into the container and launch in Docker with:

docker run -it --rm --network=host --add-host xr621:<ip address> tithomas1/cl17devnet1223

Setting up IOS-XR to allow Ansible

If not done already, generate crypto keys on the target IOS-XR device:

crypto key generate rsa

Enable SSH version 2 and set a reasonable timeout:

config t
  ssh version v2
  ssh timeout 120
  commit
  exit

This should be enough to try a simple command from your Ansible host. Make sure the target device is already defined in your inventory. In this case, we'll use the raw command as a test to pass a command over SSH to the IOS-XR CLI and dump the output. The -u parameter specifies the SSH username, the -k parameter will trigger a prompt for the SSH password, the -m specifies to use the raw command, and the -a provides the arguments to the command/module.

ansible <host> -u <username> -k -m raw -a "show version"

The first time you'll have to accept the SSH keys. You can also set up IOS-XR to use certificate-based authentication for SSH, but that's outside the scope of this README at the moment.

Example playbooks

Set an SNMP community string:

ansible-playbook playbooks/set-snmpv2.yaml --extra-vars="community=cisco123”

Create a new user account:

ansible-playbook playbooks/create_user.yaml --extra-vars="newuser=bob password=cisco"

Delete an existing user:

ansible-playbook playbooks/delete_user.yaml --extra-vars="user=bob"

Setting up IOS-XR to allow NETCONF access (for YDK)

Allow NETCONF over SSH:

config t
  ssh server netconf vrf default
  ssh server netconf port 830
  netconf-yang agent ssh
  commit
  exit

Using YDK-Gen to create custom APIs

YDK's generate tool can be used to create custom/targeted APIs for specific use cases. Or it might also be needed if a particular model isn't included in what comes with YDK (like the IETF or OpenConfig models). I ended up needing to do my own because the OpenConfig interfaces model wasn't included.

First, you need some tools on a build server. I used Ubuntu 16.04:

sudo apt-get install python-pip zlib1g-dev python-lxml libxml2-dev libxslt1-dev python-dev libboost-dev libboost-python-dev \
  libssh-dev libcurl4-openssl-dev libtool-bin libboost-all-dev libboost-log-dev libpcre3-dev libpcre++-dev libtool pkg-config \
  python3-dev python3-lxml cmake

Then you need to clone the YDK-Gen repository to a location on that server:

mkdir -p ~/projects/ydk
cd ~/projects/ydk
git clone https://github.com/CiscoDevNet/ydk-gen
cd ydk-gen

Doing this in a virtual environment is not a bad idea. If you want to use the generated API for an Ansible module, then it will need to be present in the global package list. We'll get to more on that later.

virtualenv -p python2.7 venv
source venv/bin/activate

Install YDK-Gen's module dependencies into the virtual environment (this will take a bit):

pip install -r requirements.txt

Now generate should work. As a test:

./generate.py --help

Generate the core API and install it:

./generate.py --python --core
pip install gen-api/python/ydk/dist/ydk*.tar.gz

Create an API bundle description. You can use the OSPF or MACsec ones included in this repository as examples:

vi profiles/bundles/ciscolive-ansible-ospf.json

Now we're ready to generate an API from the bundle description:

./generate.py --python --bundle profiles/bundles/ciscolive-ansible-ospf.json

You can install the generated API into the virtual environment as a test or if you're planning to use the API for something other than Ansible:

pip install gen-api/python/ciscolive_ansible_ospf-bundle/dist/ydk*.tar.gz

If you're ready to try Ansible + YDK, you'll need to back out of the virtual environment and install YDK and your custom API (if any) into the global package list. Ansible doesn't pick up the "hooks" needed to be aware of the virtual environment, therefore you have to use the global list:

deactivate
sudo pip install -r requirements.txt
sudo pip install gen-api/python/ydk/dist/ydk*.tar.gz
sudo pip install gen-api/python/ciscolive_ansible_ospf-bundle/dist/ydk*.tar.gz