I am currently looking into ansibles to store my configurations and deploy services more easily.
I have couple of iptable rules in /etc/iptables/rules.v4, which I can easily restore. Meanwhile, ansible has iptable role for configurations - hence, I am confused on what approach to take.
How do I persist this rules, especially across reboots? Should I rerun ansible every time on each reboot? I am at loss on how to best manage iptables, as other services can interact with it. How do you folks handle this? Thanks in advance!
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I second the use of nftables instead. Optimally with a pre-made role like this one: https://galaxy.ansible.com/ui/standalone/roles/ipr-cnrs/nftables/documentation/
Half off-topic, sorry: if you have some spare time on the weekend, you might want to take a look at nftables. AFAIK iptables is also just using nftables under the hood, so you are basically using a deprecated technology.
nftables is so much nicer to work with. In the end I have my custom rules (which are much saner to define than in iptables) in
/etc/nftables.conf, then I have a very simple systemd unit:[Unit] Description=Restore nftables firewall rules Before=network-pre.target [Service] Type=oneshot ExecStart=/usr/sbin/nft -f /etc/nftables.conf ExecStop=/usr/sbin/nft flush table inet filter RemainAfterExit=yes [Install] WantedBy=multi-user.targetand finally if I push updates via ansible I simply replace the file and run
nft -f /etc/nftables.conf(via ansible; on-change event).Edit: oh and as an example how the actual rules file looks like:
#!/usr/bin/nft -f add table inet filter flush table inet filter table inet filter { chain input { type filter hook input priority 0; # allow established/related connections ct state {established, related} accept # early drop of invalid connections ct state invalid drop # allow from loopback iifname lo accept # allow icmp ip protocol icmp accept ip6 nexthdr icmpv6 accept # core services tcp dport {80, 443} accept comment "allow http(s)" udp dport 443 accept comment "allow http3" # everything else reject with icmpx type port-unreachable } }and with that I have my ipv4+6 firewall that allows pings and http
Thanks, but I looked up and learned to prefer the idempotence to be handled by ansible. Ansible support iptables by default, while nftables need a plugin, so iptables it is for me.
You want something outside of IPtables like Firewalld. Ansible should only run to make changes to a existing system.
If I understand you want iptables to be persistent across reboots? Would the following be useful?:
apt-get update -y && apt-get install iptables-persistent -y service netfilter-persistent saveI have no clue about ansible as I have not explored that region of selfhosting yet. It’s on the list tho.
Generally, you set up a rule + command playbook, where the command invokes the iptables-save command.
Yeah,
ansible.builtin.iptablesmakes the changes and the task then notifies a handler to invokeiptables-save.There’s a bunch of posts about the iptables-save function of the built-in iptables module not working in many cases, so I figured it was a safer bet to suggest the playbook include an actual command invocation.
In my personal experience, the module doesnt actually save the persistent rule in about half the cases. I haven’t looked into it much, but it seems happen more on systems where systemd iptables-firewall is present. (Not trying to start a flame war)
Sorry for being unclear, that’s what I meant. Set rules using the Ansible module, make them persistent by notifying a handler that makes a cmd call.
For your information, iptables should not be used anymore. It has been deprecated. Nowadays you should use nftables, it’s successor made by the same company.