Category: Computers

Podcast Summary – Admin Admin Podcast #55

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This week sees the publication of The Admin Admin Podcast episode #55 in which I guest present (and guest introduce!) about network infrastructure. I also answer some questions about using certbot (the free TLS certificate provider), about where to put script files on Linux and a bit about MTU (Message Transfer Units) – although that’s a bit outside my area of expertise, so if I got it wrong, let them know!

The guys who host the Admin Admin podcast are a really nice, and cover a really great range of subjects about working as a server or network administrator. They have a chat room on Telegram, so if you’re interested in being an admin, it’s worth having a listen, and then maybe join the chat room!

Today I learned… Cloud-init doesn’t like you repeating the same things

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Because of templates I was building in my post “Today I learned… Ansible Include Templates”, I thought you could repeat the same sections over again. Here’s a snippet of something like what I’d built (after combining lots of templates together):

Note this is a non-working code sample!


#cloud-config
packages:
- iperf
- git

write_files:
- content: {% include 'files/public_key.j2' %}
  path: /root/.ssh/authorized_keys
  owner: root:root
  permission: '0600'
- content: {% include 'files/private_key.j2' %}
  path: /root/.ssh/id_rsa
  owner: root:root
  permission: '0600'

packages:
- byobu

write_files:
- content: |
    #!/bin/bash
    git clone {{ test_scripts }} /root/iperf_scripts
    bash /root/iperf_scripts/run_test.sh
  path: /root/run_test
  owner: root:root
  permission: '0700'

runcmd:
- /root/run_test

I’d get *bits* of it to run – basically, the last file, the last package and the last runcmd… but not all of it.

Turns out, cloud-init doesn’t like having to rebuild all the fragments together. Instead, you need to put them all together, so the write_files items, and the packages items all live in the same area.

Which, when you think about what it’s doing, which is that the parent lines are defining a variable called… well, whatever that line is, and if you replace it, it’s only going to keep the last one, then it all makes sense really!

Today I learned… that you can look at the “cloud-init” files on your target server…

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Today I have been debugging why my Cloud-init scripts weren’t triggering on my Openstack environment.

I realised that something was wrong when I tried to use the noVNC console[1] with a password I’d set… no luck. So, next I ran a command to review the console logs[2], and saw a message (now, sadly, long gone – so I can’t even include it here!) suggesting there was an issue parsing my YAML file. Uh oh!

I’m using Ansible’s os_server module, and using templates to complete the userdata field, which in turn gets populated as cloud-init scripts…. and so clearly I had two ways to debug this – prefix my ansible playbook with a few debug commands, but then that can get messy… OR SSH into the box, and look through the logs. I knew I could SSH in, so the cloud-init had partially fired, but it just wasn’t parsing what I’d submitted. I had a quick look around, and found a post which mentioned debugging cloud-init. This mentioned that there’s a path (/var/lib/cloud/instances/$UUID/) you can mess around in, to remove some files to “fool” cloud-init into thinking it’s not been run… but, I reasoned, why not just see what’s there.

And in there, was the motherlode – user-data.txt…. bingo.

In the jinja2 template I was using to populate the userdata, I’d referenced another file, again using a template. It looks like that template needs an extra line at the end, otherwise, it all runs together.

Whew!

This does concern me a little, as I had previously been using this stanza to “simply” change the default user password to something a little less complicated:


#cloud-config
ssh_pwauth: True
chpasswd:
  list: |
    ubuntu:{{ default_password }}
  expire: False

But now that I look at the documentation, I realise you can also specify that as a pre-hashed value (in which case, you would suffix that default_password item above with |password_hash('sha512')) which makes it all better again!

[1] If you run openstack --os-cloud cloud_a console url show servername gives you a URL to visit that has an HTML5 based VNC-ish client. Note the “cloud_a” and “servername” should be replaced by your clouds.yml reference and the server name or server ID you want to connect to.
[2] Like before, openstack --os-cloud cloud_a console log show servername gives you the output of the boot sequence (e.g. dmesg plus the normal startup commands, and finally, cloud-init). It can be useful. Equally, it’s logs… which means there’s a lot to wade through!

Today I learned… Ansible Include Templates

JonTheNiceGuy 1 Comment

I am building Openstack Servers with the ansible os_server module. One of these fields will accept a very long string (userdata). Typically, I end up with a giant blob of unreadable build script in this field…

Today I learned that I can use this:

---
- name: "Create Server"
  os_server:
    name: "{{ item.value.name }}"
    state: present
    availability_zone: "{{ item.value.az.name }}"
    flavor: "{{ item.value.flavor }}"
    key_name: "{{ item.value.az.keypair }}"
    nics: "[{%- for nw in item.value.ports -%}{'port-name': '{{ ProjectPrefix }}{{ item.value.name }}-Port-{{nw.network.name}}'}{%- if not loop.last -%}, {%- endif -%} {%- endfor -%}]" # Ignore this line - it's complicated for a reason
    boot_volume: "{{ ProjectPrefix }}{{ item.value.name }}-OS-Volume" # Ignore this line also :)
    terminate_volume: yes
    volumes: "{%- if item.value.log_size is defined -%}[{{ ProjectPrefix }}{{ item.value.name }}-Log-Volume]{%- else -%}{{ omit }}{%- endif -%}"
    userdata: "{% include 'templates/userdata.j2' %}"
    auto_ip: no
    timeout: 65535
    cloud: "{{ cloud }}"
  with_dict: "{{ Servers }}"

This file (/path/to/ansible/playbooks/servers.yml) is referenced by my play.yml (/path/to/ansible/play.yml) via an include, so the template reference there is in my templates directory (/path/to/ansible/templates/userdata.j2).

That template can also then reference other template files itself (using {% include 'templates/some_other_file.extension' %}) so you can have nicely complex userdata fields with loads and loads of detail, and not make the actual play complicated (or at least, no more than it already needs to be!)

Some notes from Ansible mentoring

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Last night, I met up with my friend Tim Dobson to talk about Ansible. I’m not an expert, but I’ve done a lot of Ansible recently, and he wanted some pointers.

He already had some general knowledge, but wanted some pointers on “other things you can do with Ansible”, so here are a couple of the things we did.

  • If you want to set certain things to happen as “Production” and other things to happen as “Pre-production” you can either have two playbooks (e.g. pre-prod.yml versus prod.yml) which call certain features… OR use something like this:

    ---
    - hosts: localhost
      tasks:
    - set_fact:
        my_run_state: "{% if lookup('env', 'runstate') == '' %}{{ default_run_state|default('prod') }}{% else %}{{ lookup('env', 'runstate')|lower() }}{% endif %}"
    - debug: msg="Doing prod"
      when: my_run_state == 'prod'
    - debug: msg="Doing something else"
      when: my_run_state != 'prod'

    With this, you can define a default run state (prod), override it with a group or host var (if you have, for example, a staging service or proof of concept space), or use your Environment variables to do things. In the last case, you’d execute this as follows:

    runstate=preprod ansible-playbook site.yml

  • You can tag almost every action in your plays. Here are some (contrived) examples:


    ---
    - name: Get facts from your hosts
      tags: configure
      hosts: all
    - name: Tell me all the variable data you've collected
      tags: dump
      hosts: localhost
      tasks:
        - name: Show data
          tags: show
          debug:
            var=item
          with_items: hostvars

    When you then run

    ansible-playbook test.yml --list-tags

    You get

    playbook: test.yml

      play #1 (all): Get facts from your hosts      TAGS: [configure]
          TASK TAGS: [configure]

      play #2 (localhost): Tell me all the variable data you've collected   TAGS: [dump]
          TASK TAGS: [dump, show]

    Now you can run ansible-playbook test.yml -t configure or ansible-playbook test.yml --skip-tags configure

    To show how useful this can be, here’s the output from the “–list-tags” I’ve got on a project I’m doing at work:
    playbook: site.yml

      play #1 (localhost): Provision A-Side Infrastructure  TAGS: [Functional_Testing,A_End]
          TASK TAGS: [A_End, EXCLUDE_K5_FirewallManagers, EXCLUDE_K5_Firewalls, EXCLUDE_K5_Networks, EXCLUDE_K5_SecurityGroups, EXCLUDE_K5_Servers, Functional_Testing, K5_Auth, K5_FirewallManagers, K5_Firewalls, K5_InterProjectLinks, K5_Networks, K5_SecurityGroups, K5_Servers]

      play #2 (localhost): Provision B-Side Infrastructure  TAGS: [Functional_Testing,B_End]
          TASK TAGS: [B_End, EXCLUDE_K5_Firewalls, EXCLUDE_K5_Networks, EXCLUDE_K5_SecurityGroups, EXCLUDE_K5_Servers, Functional_Testing, K5_Auth, K5_FirewallManagers, K5_Firewalls, K5_InterProjectLinks, K5_Networks, K5_SecurityGroups, K5_Servers]

      play #3 (localhost): Provision InterProject Links - Part 1    TAGS: [Functional_Testing,InterProjectLink]
          TASK TAGS: [EXCLUDE_K5_InterProjectLinks, Functional_Testing, InterProjectLink, K5_InterProjectLinks]

      play #4 (localhost): Provision InterProject Links - Part 2    TAGS: [Functional_Testing,InterProjectLink]
          TASK TAGS: [EXCLUDE_K5_InterProjectLinks, Functional_Testing, InterProjectLink, K5_InterProjectLinks]

      play #5 (localhost): Provision TPT environment        TAGS: [Performance_Testing]
          TASK TAGS: [EXCLUDE_K5_FirewallManagers, EXCLUDE_K5_Firewalls, EXCLUDE_K5_Networks, EXCLUDE_K5_SecurityGroups, EXCLUDE_K5_Servers, K5_Auth, K5_FirewallManagers, K5_Firewalls, K5_InterProjectLinks, K5_Networks, K5_SecurityGroups, K5_Servers, Performance_Testing, debug]

    This then means that if I get a build fail part-way through, or if I’m debugging just a particular part, I can run this: ansible-playbook site.yml -t Performance_Testing --skip-tags EXCLUDE_K5_Firewalls,EXCLUDE_K5_SecurityGroups,EXCLUDE_K5_Networks

Using Python-OpenstackClient and Ansible with K5

JonTheNiceGuy Leave a comment

Recently, I have used K5, which is an instance of OpenStack, run by Fujitsu (my employer). To do some of the automation tasks I have played with both python-openstackclient and Ansible. This post is going to cover how to get those tools to work with K5.

I have access to a Linux virtual machine (Ubuntu 16.04) and the Windows Subsystem for Linux in Windows 10 to run “Bash on Ubuntu on Windows”, and both accept the same set of commands.

In order to run these commands, you need a couple of dependencies. Your mileage might vary with other Linux distributions, but, for Ubuntu based distributions, run this command:

sudo apt install python-pip build-essential libssl-dev libffi-dev python-dev

Next, use pip to install the python modules you need:

sudo -H pip install shade==1.11.1 ansible cryptography python-openstackclient

If you’re only ever going to be working with a single project, you can define a handful of environment variables prefixed OS_, like this:

export OS_USERNAME=BloggsF
export OS_PASSWORD=MySuperSecretPasswordIsHere
export OS_REGION_NAME=uk-1
export OS_USER_DOMAIN_NAME=YourProjectName
export OS_PROJECT_NAME=YourProjectName-prj
export OS_PROJECT_ID=baddecafbaddecafbaddecafbaddecaf
export OS_AUTH_URL=https://identity.uk-1.cloud.global.fujitsu.com/v3
export OS_VOLUME_API_VERSION=2
export OS_IDENTITY_API_VERSION=3

But, if you’re working with a few projects, it’s probably worth separating these out into clouds.yml files. This would be stored in ~/.config/openstack/clouds.yml with the credentials for the environment you’re using:

---
clouds:
  root:
    identity_api_version: 3
    regions:
    - uk-1
    auth:
      auth_url: https://identity.uk-1.cloud.global.fujitsu.com/v3
      password: MySuperSecretPasswordIsHere
      project_id: baddecafbaddecafbaddecafbaddecaf
      project_name: YourProjectName-prj
      username: BloggsF
      user_domain_name: YourProjectName

Optionally, you can separate out the password, username or any other “sensitive” information into a secure.yml file stored in the same location (removing those lines from the clouds.yml file), like this:

---
clouds:
  root:
    auth:
      password: MySuperSecretPasswordIsHere

Now, you can use the Python based Openstack Client, using this invocation:

openstack --os-cloud root server list

Alternatively you can use the Ansible Openstack (and K5) modules, like this:

---
tasks:
- name: "Authenticate to K5"
  k5_auth:
    cloud: root
  register: k5_auth_reg
- name: "Create Network"
  k5_create_network:
    name: "Public"
    availability_zone: "uk-1a"
    state: present
    k5_auth: "{{ k5_auth_reg.k5_auth_facts }}"
- name: "Create Subnet"
  k5_create_subnet:
    name: "Public"
    network_name: "Public"
    cidr: "192.0.2.0/24"
    gateway_ip: "192.0.2.1"
    availability_zone: "uk-1a"
    state: present
    k5_auth: "{{ k5_auth_reg.k5_auth_facts }}"
- name: "Create Router"
  k5_create_router:
    name: "Public"
    availability_zone: "uk-1a"
    state: present
    k5_auth: "{{ k5_auth_reg.k5_auth_facts }}"
- name: "Attach private network to router"
  os_router:
    name: "Public"
    state: present
    network: "inf_az1_ext-net02"
    interfaces: "Public"
    cloud: root
- name: "Create Servers"
  os_server:
    name: "Server"
    availability_zone: "uk-1a"
    flavor: "P-1"
    state: present
    key_name: "MyFirstKey"
    network: "Public-Network"
    image: "Ubuntu Server 14.04 LTS (English) 02"
    boot_from_volume: yes
    terminate_volume: yes
    security_groups: "Default"
    auto_ip: no
    timeout: 7200
    cloud: root

Using riot.im as a bridge to Freenode

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Over the last few months, I’ve been using Riot.im (the client for Matrix.org) as my primary IRC client, and access to other end-to-end-encrypted chats.

A few weeks ago I decided I wanted to use my “normal” IRC nickname on Freenode, so looked into how to do it. It’s surprisingly easy, but there are a few gotchas.

Making Matrix know your password

First of all you need to message the IRC bridge bot and tell it your nickserv password: !storepass chat.freenode.net MyComplexPassword

Next, you need to chat with NickServ directly and authenticate with it: identify MyNormalNick MyComplexPassword

Lastly, you go back to your chat with the bridge bot, and tell it your nickname: !nick chat.freenode.net MyNormalNick

If, in the process of doing this, you find you can’t log in as yourself, message NickServ and tell it to release your account from being protected: release MyNormalNick MyComplexPassword

Setting topics

While the bridge bot will let you set a topic (!cmd TOPIC #channel Something) this didn’t really work for me, so instead, I use ChanServ to do it for me: topic #channel My New Topic

Just remember that you must have ops granted to you for that channel through ChanServ to be able to make such changes.

You can also set modes for people, or the channel, ban people, voice or op them through ChanServ, just send the command help in the chat to ChanServ for more guidance!

And, if you’re stuck, feel free to come ask for help! I’m (predictably) JonTheNiceGuy!

Building a Dual boot machine running Ubuntu 17.04 and Windows 10 with full-disk encryption

JonTheNiceGuy 4 Comments

This post has been revised since it was initially published on 31st March due to errors found in the resulting build. It was also missing details on the shared data drive between the two machines, so has been amended to include that.

** WARNING ** This works for me – it might not for you!

The outcome of this build will leave you with the following:

Boot up, go through the VeraCrypt bootloader, enter a password for Windows, or press escape to load the Grub bootloader where you will boot (K|L|X|)Ubuntu(| Mate| Gnome).

The Windows environment will be encrypted with VeraCrypt, an open source Full Disk Encryption technology, while the Linux environment will be encrypted using Luks. The shared volume (between Windows and Linux) will be encrypted with VeraCrypt.

PLEASE BE AWARE THAT ANY WINDOWS 10 UPGRADES WILL FAIL TO APPLY AS IT WILL NOT RECOGNISE THE VERACRYPT FILE SYSTEM! To resolve this, decrypt the Windows volume, perform the upgrade, re-encrypt it, then transfer the new recovery ISO image to the boot volume, following the method below. Yes, this will take some time. No, you don’t need to decrypt the data volume. Yes, you can use that data volume to shunt the ISO image around.

LATE EDIT 2020-01-06: I’ve just spotted a link to this post over on Level1Techs. In that post, someone asked if the broken upgrades is still a thing. Turns out that since I wrote this in 2017, it’s not been fixed. Now, I should stress, I’ve stopped using this layout as I went all-Linux on that machine, but… it might work for you now?! Also, shout out to 92aceshigh for referencing this post, and glad something I wrote helped you! ☺

Step 1:Create your partition table

My partition table, for a 320GB Disk looks (roughly) like this:

Partition 1: 20GB – Linux /Boot (ext2, plus space for ISO files for random booting)
Partition 2: 60GB – Windows C:\ (NTFS VeraCrypt)
Partition 3: 72GB – Linux Physical Volume (LVM PV, Luks Encrypted)
– logical volume 1: 16Gb Swap (Linux Swap)
– logical volume 2: 60Gb Linux (ext4)
Partition 4: 156GB – Shared Volume (NTFS, VeraCrypt)

I performed this using GParted in the Gnome Live image using the GParted. Some rational here:

  1. The first partition also allows me to add other ISOs if I want to boot them.
  2. I have 4GB RAM, this gives me some extra space to allow me to hibernate, but also… 4Gb. Ugh.
  3. I then split my Linux and Windows partitions into two equal parts.

Step 2: Use Cryptsetup to format the disk

The following steps need to be run as root.

sudo -i

Step 2a: Format the partitions as LUKS

cryptsetup luksFormat -y -v /dev/sda3

Step 2b: Open the LUKS volume

cryptsetup luksOpen /dev/sda3 lvm-pv

Step 2c: Create the LVM Physical Volume over the LUKS volume

vgcreate vg00 /dev/mapper/lvm-pv

Step 2d: Define the LVM Logical Volumes over the LVM Physical Volume

lvcreate -n lv00_swap -L 16G vg00       # Define 16GB Swap Space
lvcreate -n lv01_root -l +100%FREE vg00 # Define the rest of vg00 as /

LEAVE YOUR TERMINAL OPEN

Step 3: Install your Linux distribution.

Note that when you perform your install, when you get to the partitioning screen, select “Manual”, and then pick out the following volumes:

/dev/mapper/vg00-lv01_root = ext4 formatted, mount point: /
/dev/mapper/vg00-lv00_swap = swap
/dev/sda1 = ext2, format, mount point: /boot

Select the boot volume of /dev/sda. But wait, I hear you say, Windows has a well know history of nuking Grub partitions… Well, we’ll sort that in a bit…

DON’T EXIT THE LIVE SESSION ONCE THE INSTALL HAS FINISHED (select “Continue Testing”).

Step 4: Make your machine actually able to boot

Go back to your terminal session.  It should still be logged in as root. We need to re-mount all the partitions…

Step 4a: Mount your volumes

mount /dev/mapper/vg00-lv01_root /target
mount /dev/sda1 /target/boot
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /target$i; done

Step 4b: Swap to the “Target” filesystem

chroot /target

Step 4c: Setup your volumes to prompt for cryptographic keys

echo "LinuxRoot UUID=`blkid | grep sda3 | cut -d\\\" -f2` none luks" > /etc/crypttab

Step 4d: Update the boot volume to use these changes

update-initramfs -u

Step 4e: Ensure Grub is also installed to the MBR for testing

grub-install --force /dev/sda1
chattr +i /boot/grub/i386-pc/core.img
update-grub

The first part installs grub to the boot position, even though it doesn’t like it, and the second forces the core file to be unchangeable… I’m not exactly sure of the impact of this, but it’s the only way to do the next part of this process. The last bit makes sure that you’ve got the latest grub config files installed.

Step 5: Reboot and test

Just check to make sure the machine boots OK!

You should have a booting Ubuntu derivative with an encrypted file system. Awesome.

Now let’s install Windows!

Step 6: Install Windows and Veracrypt.

You should boot from your install media, when you get to the partition selector, there should only be a single NTFS partition for it to use. Use it.

Install the latest version of Veracrypt from https://veracrypt.codeplex.com/

Once it’s installed, go to System, Encrypt System Partition/Drive, “Normal” system encryption, Windows System Partition, Multi-Boot (accept the warning), Boot Drive “Yes”, Single Disk, “Non-Windows Boot Loader” – No, and then… let it go through all the rest of the steps. There will be one stage where it asks you to create a rescue disk. Just save it for later. Once the encryption settings are collected, it will do a test (which is basically just rebooting to the boot loader, having you put in your password and going back into Windows), and then let it start performing the encryption.

Once the encryption finishes, reboot the computer, enter the decryption password and test it boots to Windows OK. Then reboot it again and press escape instead of putting in the password. It will boot to your Ubuntu system.

So, there you have it. One Dual-Boot system with encrypted disks everywhere!

Step 7: Setting up the shared volume.

After you’ve got the Ubuntu and Windows volumes sorted out, next we need the shared data volume to be organised. You’ll need Veracrypt for Ubuntu. Use the following to install the Veracrypt package for Ubuntu:

sudo add-apt-repository ppa:unit193/encryption
sudo apt-get update
sudo apt-get install veracrypt

Once that’s installed, boot back into Windows and create a new volume – perhaps V: for Veracrypt, or E: for Encrypted – your choice, but make sure you create it using the same password that you used for the Windows partition.

Format this new volume with either NTFS or FAT32 so that you can mount it under either operating system. I chose NTFS.

Now, you need to go into Veracrypt’s Settings menu, and select “System Encryption Settings”. Tick “Cache pre-boot authentication password in driver memory” (be aware, this means that if your machine is compromised when powered up, the password could be recovered), then OK. This may prompt you to accept the UAC at this point.

Next, with the mounted volume selected, go to the “Favorites” menu, and choose “Add to System Favorites”. In the screen which comes up, select the box under “Global Settings” which says “Mount system favorite volumes when Windows starts (in the initial phase of the startup procedure)”. There will be a warning about passwords that appears. Click OK.

You may, at this point, want to move certain aspects of your Windows desktop (e.g. the “My Documents” location) to the new mounted drive.

On the Linux OS, become root, with sudo, and then add the following lines to your crontab:

@reboot mkdir -p /shared_storage 
@reboot veracrypt --text --non-interactive --fs-options=uid=1000,gid=1000,umask=0077 --password="YOURSUPERSECUREPASSWORD" /dev/sda4 /shared_storage

These assume that your login user’s ID is 1000 (you can check that by running the command “id” as your logged in user), that you want to use “/shared_storage” as the mount point (it stops Ubuntu treating it as a “Mountable Volume” if it’s not in your home directory and not in /mnt or /media). These options also mean that only that user (and root) can access any of the files in that partition (although, it is only you on this laptop… right?), which means you can safely use it for any files which check user permissions before allowing you to access them (e.g. SSH keys). I then set up a symbolic link to /home/MYUSERACCOUNT/Documents into the /shared_storage/Documents directory, and /home/MYUSERACCOUNT/.ssh into the /shared_storage/SSH_Keys directory.

Citataions

The following list of resources helped me out when I was struggling with what to do next! They may not be canonical sources, but they helped.

  1. http://thesimplecomputer.info/full-disk-encryption-with-ubuntu – This is what got me started on this little journey!
  2. http://askubuntu.com/questions/161689/how-do-i-get-grub2-to-boot-a-truecrypt-encrypted-mbr – How to add the Veracrypt recovery disk to your Grub boot partition. Note, I do it slightly differently to this now.
  3. http://askubuntu.com/questions/711801/i-deleted-files-in-boot-now-cant-boot-linux – I may have done this. It tells you how to put all your important files back for booting purposes :)
  4. https://www.youtube.com/watch?v=Z1yWbBIqh1o – Walk through of installing Veracrypt to Windows 10. I used this to see some of the terms after I’d already installed Veracrypt. I don’t quite follow the same route as him though.
  5. https://www.linux.com/blog/how-full-encrypt-your-linux-system-lvm-luks – Using LVM inside Luks for the full-Linux disk (this was why I’ve re-written this post)
  6. https://wiki.archlinux.org/index.php/Dm-crypt/Encrypting_an_entire_system – Some details around how the Luks stuff all works

I may or may not have reinstalled Windows and Kubuntu about 20 times during this process, cursing myself for starting the whole damn process off in the first place!!!

Working with complicated template data UserData in Ansible

JonTheNiceGuy Leave a comment

My new job means I’m currently building a lot of test boxes with Ansible, particularly OpenStack guests. This means I’m trying to script as much as possible without actually … getting my hands dirty with the actual “logging into it and running things” perspective.

This week, I hit a problem standing up a popular firewall vendor’s machine with Ansible, because I was trying to bypass the first-time-wizard… anyway, it wasn’t working, and I couldn’t figure out why. I talked to my colleague [mohclips] and he eventually told me that I needed to use a template, because what I was trying to do was too complicated.

But, damn him, I knew that wasn’t the answer :)

Anyway, I found this comment on a ticket, which lead me to the following… if you’re finding that your userdata: variable in the os_server module of Ansible isn’t working, you might need to wrap it up like this:

userdata: |
  {%- raw -%}#!/bin/bash
  # Kill script if the pipe fails
  set -euf -o pipefail
  # Write everything from this point on to Syslog
  echo " == Set admin credentials == "
  clish -c 'set user admin password-hash {% endraw -%}{{ default_password|password_hash('sha512') }}{%- raw -%}' -s
  {% endraw %}

Note that, if you have a space before your variable, use {% endraw -%} and if you’ve a space after it, use {%- raw %} as the hyphen means “ditch all the spaces before/after this command”.

Use your Debian System with as an iBeacon for Home Automation

JonTheNiceGuy Leave a comment

I have been using the Home-Assistant application at home to experiment with Home Automation.

One thing I’ve found is that the Raspberry Pi is perfect for a few of the monitoring things that I wanted it to do (see also https://github.com/JonTheNiceGuy/home-assistant-configs for more details of what I’m doing there!).

I’m using the OwnTracks application to talk to an MQTT server, but I could also do with it knowing where I am in the house, so I looked around for some details on iBeacons.

iBeacon is an Apple standard, but it’s very easy to configure on Linux systems. I took some pointers from this article and wrote up a script to turn on the iBeacon on my Raspbian Raspberry Pi 3.

Configuring the Script

When you first run it as root, it will pre-populate a config file in /etc/iBeacon.conf. Edit it and run the script again.

Running the script

This script needs to be run as root, so to test it, or to reconfigure the beacon, run sudo /root/iBeacon.sh (or wherever you put it!)

Making it persistent

To be honest, at this point, I’d probably just stick this into my root Crontab file by adding this line:

@reboot /root/iBeacon.sh | logger

Again, replace /root/iBeacon.sh with wherever you put it!

Please visit this link to see the script and make suggestions on improvements.