Networking/Procedures

Network Related procedures

Ansible procedures

using Ansible with a Rasbperry Pi

dd raspbian image (use the 02-09 one to avoid usb issues)
boot pi
watch dhcp logs on boole
ssh pi@ip
passwd: raspberry

sudo raspi-config
update it
expand filesystem
change password
boot to console
advanced options -> hostname

cd /etc/network
edit interfaces to get a static ip
reboot

on boole:

add hostname to fwd and rev. dns, don't forget to commit your changes.

log into adminstuff with ssh keys forwarded

add hostname to /etc/ansible/hosts in both the [lhshosts] and [rpis]
sections, and [doorbot] if it's a doorbot, make the syslocation="something sensible"

then:

if it's a replacement for an old machine then:

ssh-keygen -R hostname
ssh-keygen -R hostname.lan.london.hackspace.org.uk
ssh-keygen -R ipv4 address (?)
ssh-keygen -R ipv6 address (?)

then:

cd /etc/ansible

install python-apt which ansible needs:

ansible -vvv -u pi -k -s -m command -a "apt-get -y install python-apt" "hostname"

Then run it

ansible-playbook -u pi -s -k -l "hostname" lhs/site.yml

The 2nd one will add our users, ssh keys, packages, etc etc.

notes:

not sure how resolv.conf gets setup, I thought having:

iface eth0 inet static
        [...]
        dns-nameservers 172.31.24.2
        dns-search lan.london.hackspace.org.uk

Would sort it, but maybe that dosn't and we got lucky from dhcp?

The dns stuff in /etc/network/interfaces appears to be bogus and resolv.conf needs to be
done manually, add to ansible.

Bootstrapping a new machine to a static ip

Login to the new install and find it's ip, make sure you know the root password, or have an sshkey for the root account.

Choose a hostname for your new machine.

Log in to boole, and as root cd /etc/bind, and edit lan.london.hackspace.org.uk. and 24.31.172.in-addr.arpa. to add your new host, remember the new static ip you choose.

There is only a few static ip's left, you may end up needing to shrink the dhcp range and change the dhcpserver config on boole as well.

zkt-signer -v -r to sign and push out your changes.

Check that the hostname works in fwd and reverse dns.

and git commit your changes and log out of boole.

on adminstuff edit /etc/ansible/hosts, add:

<ip> syslocation="something" lhs_host=<hostname>

to at least [lhshosts], you probably want [ldap-clients] as well, and maybe some other sections, depending on what you want.

then edit /etc/ansible/lhs/vars/defaults.yml , adding your host and the last octet of the new static ip to the hosts: section

now ssh to the host to check that ssh works:

ssh root@<ip>

You may need to fix old cached pub keys, and/or allowing root to ssh to your new machine with a password ( PermotRootLogin yes in /etc/ssh/sshd_config on the machine you are setting up).

Now you can run ansible. This example assumes you are using a password for root

cd /etc/ansible
ansible-playbook -l "<ip>" -k -u root lhs/site.yml

and hopefully ansible should run ok and set everything up!

Note that ansible will change the root password, hopefully you've got a way to get back in (either you are an admin in ansible, or in the Admins group in ldap, in either case you can login as yourself and then sudo).

Now reboot the new machine, it should come back with the static ip. double check that it's right.

Now edit /etc/ansible/hosts on adminstuff again and in the entries you added earlier change <ip> to the machines new full hostname.

Now run ansible again (needed to fix the snmp config), if it's an ldap client you'll have to use your ldap password - (You could always add your ssh key to your account on the new machine).

git commit your changes on adminstuff.

and you are done!

Removing an admin

edit /etc/ansible/lhs/vars/defaults.yml, remove them from users, add them to disable_users, then re-run ansible.

Ansible Troubleshooting

problem, ansible dies in the snmp config cos it can't find a default ipv4 address.

fix: make sure the machine has an ipv4 default route

problem, the sshfp stuff just has hostname. rather than hostname.lan.london.hackspace.org.uk.

fix: edit /etc/hosts on the effected machine so that both the long and short versions of the hostname are in there.

Making someone an admin

• Ask them for an ssh pubkey, prefered username, and the email address they want to use. If they already have an LDAP account then use the same username and email!
• Explain that they will get some automated emails from monitoring systems and cron tasks, if the emails indicate problems then they have a part of the responsibility to fix the problems :)
• Point them at https://bugs.london.hackspace.org.uk/projects/london-hackspace/ encourage them to fix issues and add things that they think need fixing.
• On adminstuff add the ssh pubkey as /etc/ansible/lhs/roles/common/files/<username>.pub
• edit /etc/ansible/lhs/vars/defaults.yml and add there details under the users: section
• run ansible as usual
• on turing (which you may not have access to, if not ask a trustee to do it for you)
  • add there email to london-hackspace-sysadmins in /etc/aliases
  • run newaliases
  • add them to the Admins LDAP group: smbldap-groupmod -m <username> Admins