"Tower" by " Yijun Chen" on Flickr

Building a Gitlab and Ansible Tower (AWX) Demo in Vagrant with Ansible

TL;DR – I created a repository on GitHub‌ containing a Vagrantfile and an Ansible Playbook to build a VM running Docker. That VM hosts AWX (Ansible Tower’s upstream open-source project) and Gitlab.

A couple of years ago, a colleague created (and I enhanced) a Vagrant and Ansible playbook called “Project X” which would run an AWX instance in a Virtual Machine. It’s a bit heavy, and did a lot of things to do with persistence that I really didn’t need, so I parked my changes and kept an eye on his playbook…

Fast-forward to a week-or-so ago. I needed to explain what a Git/Ansible Workflow would look like, and so I went back to look at ProjectX. Oh my, it looks very complex and consumed a lot of roles that, historically, I’ve not been that impressed with… I just needed the basics to run AWX. Oh, and I also needed a Gitlab environment.

I knew that Gitlab had a docker-based install, and so does AWX, so I trundled off to find some install guides. These are listed in the playbook I eventually created (hence not listing them here). Not all the choices I made were inspired by those guides – I wanted to make quite a bit of this stuff “build itself”… this meant I wanted users, groups and projects to be created in Gitlab, and users, projects, organisations, inventories and credentials to be created in AWX.

I knew that you can create Docker Containers in Ansible, so after I’d got my pre-requisites built (full upgrade, docker installed, pip libraries installed), I add the gitlab-ce:latest docker image, and expose some ports. Even now, I’m not getting the SSH port mapped that I was expecting, but … it’s no disaster.

I did notice that the Gitlab service takes ages to start once the container is marked as running, so I did some more digging, and found that the uri module can be used to poll a URL. It wasn’t documented well how you can make it keep polling until you get the response you want, so … I added a PR on the Ansible project’s github repo for that one (and I also wrote a blog post about that earlier too).

Once I had a working Gitlab service, I needed to customize it. There are a bunch of Gitlab modules in Ansible but since a few releases back of Gitlab, these don’t work any more, so I had to find a different way. That different way was to run an internal command called “gitlab-rails”. It’s not perfect (so it doesn’t create repos in your projects) but it’s pretty good at giving you just enough to build your demo environment. So that’s getting Gitlab up…

Now I need to build AWX. There’s lots of build guides for this, but actually I had most luck using the README in their repository (I know, who’d have thought it!??!) There are some “Secrets” that should be changed in production that I’m changing in my script, but on the whole, it’s pretty much a vanilla install.

Unlike the Gitlab modules, the Ansible Tower modules all work, so I use these to create the users, credentials and so-on. Like the gitlab-rails commands, however, the documentation for using the tower modules is pretty ropey, and I still don’t have things like “getting your users to have access to your organisation” working from the get-go, but for the bulk of the administration, it does “just work”.

Like all my playbooks, I use group_vars to define the stuff I don’t want to keep repeating. In this demo, I’ve set all the passwords to “Passw0rd”, and I’ve created 3 users in both AWX and Gitlab – csa, ops and release – indicative of the sorts of people this demo I ran was aimed at – Architects, Operations and Release Managers.

Maybe, one day, I’ll even be able to release the presentation that went with the demo ;)

On a more productive note, if you’re doing things with the tower_ modules and want to tell me what I need to fix up, or if you’re doing awesome things with the gitlab-rails tool, please visit the repo with this automation code in, and take a look at some of my “todo” items! Thanks!!

Featured image is “Tower” by “Yijun Chen” on Flickr and is released under a CC-BY-SA license.

"funfair action" by "Jon Bunting" on Flickr

Improving the speed of Azure deployments in Ansible with Async

Recently I was building a few environments in Azure using Ansible, and found this stanza which helped me to speed things up.

  - name: "Schedule UDR Creation"
    azure_rm_routetable:
      resource_group: "{{ resource_group }}"
      name: "{{ item.key }}_udr"
    loop: "{{ routetables | dict2items }}"
    loop_control:
        label: "{{ item.key }}_udr"
    async: 1000
    poll: 0
    changed_when: False
    register: sleeper

  - name: "Check UDRs Created"
    async_status:
      jid: "{{ item.ansible_job_id }}"
    register: sleeper_status
    until: sleeper_status.finished
    retries: 500
    delay: 4
    loop: "{{ sleeper.results|flatten(levels=1) }}"
    when: item.ansible_job_id is defined
    loop_control:
      label: "{{ item._ansible_item_label }}"

What we do here is to start an action with an “async” time (to give the Schedule an opportunity to register itself) and a “poll” time of 0 (to prevent the Schedule from waiting to be finished). We then tell it that it’s “never changed” (changed_when: False) because otherwise it always shows as changed, and to register the scheduled item itself as a “sleeper”.

After all the async jobs get queued, we then check the status of all the scheduled items with the async_status module, passing it the registered job ID. This lets me spin up a lot more items in parallel, and then “just” confirm afterwards that they’ve been run properly.

It’s not perfect, and it can make for rather messy code. But, it does work, and it’s well worth giving it the once over, particularly if you’ve got some slow-to-run tasks in your playbook!

Featured image is “funfair action” by “Jon Bunting” on Flickr and is released under a CC-BY license.

A web browser with the example.com web page loaded

Working around the fact that Ansible’s URI module doesn’t honour the no_proxy variable…

An Ansible project I’ve been working on has tripped me up this week. I’m working with some HTTP APIs and I need to check early whether I can reach the host. To do this, I used a simple Ansible Core Module which lets you call an HTTP URI.

- uri:
    follow_redirects: none
    validate_certs: False
    timeout: 5
    url: "http{% if ansible_https | default(True) %}s{% endif %}://{{ ansible_host }}/login"
  register: uri_data
  failed_when: False
  changed_when: False

This all seems pretty simple. One of the environments I’m working in uses the following values in their environment:

http_proxy="http://192.0.2.1:8080"
https_proxy="http://192.0.2.1:8080"
no_proxy="10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24"

And this breaks the uri module, because it tries to punt everything through the proxy if the “no_proxy” contains CIDR values (like 192.0.2.0/24) (there’s a bug raised for this)… So here’s my fix!

- set_fact:
    no_proxy_match: |
      {
        {% for no_proxy in (lookup('env', 'no_proxy') | replace(',', '') ).split() %}
          {% if no_proxy| ipaddr | type_debug != 'NoneType' %}
            {% if ansible_host | ipaddr(no_proxy) | type_debug != 'NoneType' %}
              "match": "True"
            {% endif %}
          {% endif %}
        {% endfor %}
      }

- uri:
    follow_redirects: none
    validate_certs: False
    timeout: 5
    url: "http{% if ansible_https | default(True) %}s{% endif %}://{{ ansible_host }}/login"
  register: uri_data
  failed_when: False
  changed_when: False
  environment: "{ {% if no_proxy_match.match | default(False) %}'no_proxy': '{{ ansible_host }}'{% endif %} }"

So, let’s break this down.

The key part to this script is that we need to override the no_proxy environment variable with the IP address that we’re trying to address (so that we’re not putting 16M addresses for 10.0.0.0/8 into no_proxy, for example). To do that, we use the exact same URI block, except for the environment line at the end.

In turn, the set_fact block steps through the no_proxy values, looking for IP Addresses to check ({% if no_proxy | ipaddr ... %}‌ says “if the no_proxy value is an IP Address, return it, but if it isn’t, return a ‘None’ value”) and if it’s an IP address or subnet mask, it checks to see whether the IP address of the host you’re trying to reach falls inside that IP Address or Subnet Mask ({% if ansible_host | ipaddr(no_proxy) ... %} says “if the ansible_host address falls inside the no_proxy range, then return it, otherwise return a ‘None’ value”). Both of these checks say “If this previous check returns anything other than a ‘None’ value, do the next thing”, and on the last check, the “next” thing is to set the flag ‘match’ to ‘true’. When we get to the environment variable, we say “if match is not true, it’s false, so don’t put a value in there”.

So that’s that! Yes, I could merge the set_fact block into the environment variable, but I do end up using that a fair amount. And really, if it was merged, that would be even MORE complicated to pick through.

I have raised a pull request on the Ansible project to update the documentation, so we’ll see whether we end up with people over here looking for ways around this issue. If so, let me know in the comments below! Thanks!!

Creating Self Signed certificates in Ansible

In my day job, I sometimes need to use a self-signed certificate when building a box. As I love using Ansible, I wanted to make the self-signed certificate piece something that was part of my Ansible workflow.

Here follows a bit of basic code that you could use to work through how the process of creating a self-signed certificate would work. I would strongly recommend using something more production-ready (e.g. LetsEncrypt) when you’re looking to move from “development” to “production” :)

---
- hosts: localhost
  vars:
  - dnsname: your.dns.name
  - tmppath: "./tmp/"
  - crtpath: "{{ tmppath }}{{ dnsname }}.crt"
  - pempath: "{{ tmppath }}{{ dnsname }}.pem"
  - csrpath: "{{ tmppath }}{{ dnsname }}.csr"
  - pfxpath: "{{ tmppath }}{{ dnsname }}.pfx"
  - private_key_password: "password"
  tasks:
  - file:
      path: "{{ tmppath }}"
      state: absent
  - file:
      path: "{{ tmppath }}"
      state: directory
  - name: "Generate the private key file to sign the CSR"
    openssl_privatekey:
      path: "{{ pempath }}"
      passphrase: "{{ private_key_password }}"
      cipher: aes256
  - name: "Generate the CSR file signed with the private key"
    openssl_csr:
      path: "{{ csrpath }}"
      privatekey_path: "{{ pempath }}"
      privatekey_passphrase: "{{ private_key_password }}"
      common_name: "{{ dnsname }}"
  - name: "Sign the CSR file as a CA to turn it into a certificate"
    openssl_certificate:
      path: "{{ crtpath }}"
      privatekey_path: "{{ pempath }}"
      privatekey_passphrase: "{{ private_key_password }}"
      csr_path: "{{ csrpath }}"
      provider: selfsigned
  - name: "Convert the signed certificate into a PKCS12 file with the attached private key"
    openssl_pkcs12:
      action: export
      path: "{{ pfxpath }}"
      name: "{{ dnsname }}"
      privatekey_path: "{{ pempath }}"
      privatekey_passphrase: "{{ private_key_password }}"
      passphrase: password
      certificate_path: "{{ crtpath }}"
      state: present

One to read: A Beginner’s Guide to IPFS

One to read: “A Beginner’s Guide to IPFS”

Ever wondered about IPFS (the “Inter Planetary File System”) – a new way to share and store content. This doesn’t rely on a central server (e.g. Facebook, Google, Digital Ocean, or your home NAS) but instead uses a system like bittorrent combined with published records to keep the content in the system.

If your host goes down (where the original content is stored) it’s also cached on other nodes who have visited your site.

These caches are cleared over time, so are suitable for short outages, or you can have other nodes who “pin” your content (and this can be seen as a paid solution that can fund hosts).

IPFS is great at hosting static content, but how to deal with dynamic content? That’s where PubSub comes into play (which isn’t in this article). There’s a database service which sits on IPFS and uses PubSub to sync data content across the network, called Orbit-DB.

It’s looking interesting, especially in light of the announcement from CloudFlare about their introduction of an available IPFS gateway.

It’s looking good for IPFS!

This was automatically posted from my RSS Reader, and may be edited later to add commentary.

One to read/watch: IPsec and IKE Tutorial

Ever been told that IPsec is hard? Maybe you’ve seen it yourself? Well, Paul Wouters and Sowmini Varadhan recently co-delivered a talk at the NetDev conference, and it’s really good.

Sowmini’s and Paul’s slides are available here: https://www.files.netdevconf.org/d/a18e61e734714da59571/

A complete recording of the tutorial is here. Sowmini’s part of the tutorial (which starts first in the video) is quite technically complex, looking at specifically the way that Linux handles the packets through the kernel. I’ve focused more on Paul’s part of the tutorial (starting at 26m23s)… but my interest was piqued from 40m40s when he starts to actually show how “easy” configuration is. There are two quick run throughs of typical host-to-host IPsec and subnet-to-subnet IPsec tunnels.

A key message for me, which previously hadn’t been at all clear in IPsec using {free,libre,open}swan is that they refer to Left and Right as being one party and the other… but the node itself works out if it’s “left” or “right” so the *SAME CONFIG* can be used on both machines. GENIUS.

Also, when you’re looking at the config files, anything prefixed with an @ symbol is something that doesn’t need resolving to something else.

It’s well worth a check-out, and it’s inspired me to take another look at IPsec for my personal VPNs :)

I should note that towards the end, Paul tried to run a selection of demonstrations in Opportunistic Encryption (which basically is a way to enable encryption between two nodes, even if you don’t have a pre-established VPN with them). Because of issues with the conference wifi, plus the fact that what he’s demoing isn’t exactly production-grade yet, it doesn’t really work right, and much of the rest of the video (from around 1h10m) is him trying to show that working while attendees are running through the lab, and having conversations about those labs with the attendees.

Ansible Behaviour Change

For those of you who are working with #Ansible… Ansible 2.5 is out, and has an unusual documentation change around a key Ansible concept – `with_` loops Where you previously had:

with_dict: "{{ your_fact }}"
or
with_subelements:
- "{{ your_fact }}"
- some_subkey

This now should be written like this:

loop: "{{ lookup('dict', your_fact) }}"
and
loop: "{{ lookup('subelements', your_fact, 'some_subkey') }}"

Fear not, I hear you say, It’s fine, of course the documentation suggests that this is “how it’s always been”…… HA HA HA Nope. This behaviour is new as of 2.5, and needs ansible to be updated to the latest version. As far as I can tell, there’s no way to indicate to Ansible “Oh, BTW, this needs to be running on 2.5 or later”… so I wrote a role that does that for you.

ansible-galaxy install JonTheNiceGuy.version-check

You’re welcome :)

More useful URLs:

Defining Networks with Ansible

In my day job, I’m using Ansible to provision networks in OpenStack. One of the complaints I’ve had about the way I now define them is that the person implementing the network has to spell out all the network elements – the subnet size, DHCP pool, the addresses of the firewalls and names of those items. This works for a manual implementation process, but is seriously broken when you try to hand that over to someone else to implement. Most people just want something which says “Here is the network I want to implement – 192.0.2.0/24″… and let the system make it for you.

So, I wrote some code to make that happen. It’s not perfect, and it’s not what’s in production (we have lots more things I need to add for that!) but it should do OK with an IPv4 network.

Hope this makes sense!

---
- hosts: localhost
  vars:
  - networks:
      # Defined as a subnet with specific router and firewall addressing
      external:
        subnet: "192.0.2.0/24"
        firewall: "192.0.2.1"
        router: "192.0.2.254"
      # Defined as an IP address and CIDR prefix, rather than a proper network address and CIDR prefix
      internal_1:
        subnet: "198.51.100.64/24"
      # A valid smaller network and CIDR prefix
      internal_2:
        subnet: "203.0.113.0/27"
      # A tiny CIDR network
      internal_3:
        subnet: "203.0.113.64/30"
      # These two CIDR networks are unusable for this environment
      internal_4:
        subnet: "203.0.113.128/31"
      internal_5:
        subnet: "203.0.113.192/32"
      # A massive CIDR network
      internal_6:
        subnet: "10.0.0.0/8"
  tasks:
  # Based on https://stackoverflow.com/a/47631963/5738 with serious help from mgedmin and apollo13 via #ansible on Freenode
  - name: Add router and firewall addressing for CIDR prefixes < 30     set_fact:       networks: >
        {{ networks | default({}) | combine(
          {item.key: {
            'subnet': item.value.subnet | ipv4('network'),
            'router': item.value.router | default((( item.value.subnet | ipv4('network') | ipv4('int') ) + 1) | ipv4),
            'firewall': item.value.firewall | default((( item.value.subnet | ipv4('broadcast') | ipv4('int') ) - 1) | ipv4),
            'dhcp_start': item.value.dhcp_start | default((( item.value.subnet | ipv4('network') | ipv4('int') ) + 2) | ipv4),
            'dhcp_end': item.value.dhcp_end | default((( item.value.subnet | ipv4('broadcast') | ipv4('int') ) - 2) | ipv4)
          }
        }) }}
    with_dict: "{{ networks }}"
    when: item.value.subnet | ipv4('prefix') < 30   - name: Add router and firewall addressing for CIDR prefixes = 30     set_fact:       networks: >
        {{ networks | default({}) | combine(
          {item.key: {
            'subnet': item.value.subnet | ipv4('network'),
            'router': item.value.router | default((( item.value.subnet | ipv4('network') | ipv4('int') ) + 1) | ipv4),
            'firewall': item.value.firewall | default((( item.value.subnet | ipv4('broadcast') | ipv4('int') ) - 1) | ipv4)
          }
        }) }}
    with_dict: "{{ networks }}"
    when: item.value.subnet | ipv4('prefix') == 30
  - debug:
      var: networks