From e78e60be9fbdd43e8d52bb4576350e7895cee6e6 Mon Sep 17 00:00:00 2001
From: breadcat
Date: Fri, 25 Feb 2022 19:46:53 +0000
Subject: Add Oracle Alpine ARM post

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+---
+title: "Oracle Alpine Linux ARM server"
+date: 2022-02-16T18:59:00
+tags: ["Guides", "Linux", "Networks", "Servers", "Software"]
+---
+
+After finding a post about [creating a minecraft server in bash](https://sdomi.pl/weblog/15-witchcraft-minecraft-server-in-bash/) on Reddit I started reading through the rest of [sdomi's blog](https://sdomi.pl/weblog/) and [one post in particular](https://sdomi.pl/weblog/12-bootstrapping-alpine-on-oraclecloud/) caught my eye. It details running an aarch64 version of Alpine Linux on a free tier Oracle Cloud server. Now this combination of words ticks pretty much every box I have going. While the guide is a little brief on details it works great and offers some suggestions at the end I'd like to build upon. So without further ado, let's go.
+
+## Initial Instance
+
+After creating your account, create your compute instance. While creating this, change the following under 'Image and shape':
+* Change the Image to 'Oracle Linux version 7.9' (correct at time of writing)
+* Change the Shape to be 'Ampere, Arm-based processor'
+
+I uploaded my own public key, but you can also download pre-generated ones. All the other defaults are fine. Click create and wait the five or so minutes for the instance to be created.
+
+Once created, log in via the 'Public IP address' on the instance details page, using your SSH private key with the username `opc`. With this, you should be logged in and you can elevate to root using `sudo su -`.
+
+Now [follow the rest of the guide](https://sdomi.pl/weblog/12-bootstrapping-alpine-on-oraclecloud/) and reboot into your newly booted Alpine VM.
+
+## Upgrading to Edge
+
+The first thing I did once rebooted was upgrading from version `3.13` of Alpine to the latest `edge` version. This is entirely optional, but I prefer to run the latest versions of applications where possible.
+To do this, edit your repositories file:
+```
+vi /etc/apk/repositories
+```
+Replace any references to `v3.13` with `edge`, then run the following to update:
+```
+apk --update upgrade
+```
+Reboot again, and you should be running the latest version. Feel free to add any additional pacakges using `apk --update add neofetch neovim` etc.
+
+## Shuffling Partitions
+
+As mentioned in the guide, Alpine is currently installed on the /old/ swap `/dev/sda2` partition. You can now delete your old Oracle partiton to regain some 40GB space.
+
+```
+fdisk /dev/sda
+p
+d
+3
+w
+```
+Which should (remember to read the printed output!) delete the old XFS Oracle partition.
+
+While we're here, you can also change the partition type on `/dev/sda2` from Linux Swap to Linux Filesystem
+```
+fdisk /dev/sda
+t
+2
+linux
+w
+```
+
+You can now write your changes with `w` and quit with `q`.
+
+For the next stage, we need to expand the size of our Alpine ext4 partition.
+```
+apk add parted
+parted /dev/sda
+p
+resizepart
+2
+100%
+quit
+```
+
+With this size now increased, you can uninstall parted with `apk del parted` and actually go about resizing it, using the following command `resize2fs /dev/sda2`.
+Once completed, reboot again and check your partitions using `fdisk -l`.
+
+## Securing SSH
+
+As mentioned in the guide, all the above remote work was done using password authentication which we're not a fan of in the long term. I did this from my /other/ server for easy access to my SSH keys:
+```
+ssh-copy-id -i your_ssh_key.pub root@server.ip.address
+```
+Verify your `.ssh/authorized_keys` file looks correct, ensure you can connect using SSH and public key authentication. If this works, you can now disable password authentication with the following:
+```
+nvim /etc/ssh/sshd_config
+```
+Search for the `#PasswordAuthentication yes` line, uncomment it and change this to `no`. Here you can also change the port SSH is active on, predictably with the `Port 22` line, be sure to check the Firewall section however if you do change this.
+
+Once you're done, save the file and restart the SSH daemon using `rc-service sshd restart`.
+
+Congratulations, you've now (reasonably) secured your SSH server. You can also go one step above with this and disallow root logins, and create a new non-root user, but that's outside the scope of this guide.
+
+## Swap
+One last thing that needs attention is that during the installation of Alpine we used the 8GB swap partition as our root. Without going into re-partitioning we can simply create a new swap file of whatever size is required (in this example, I'm using 2GB). To do this, simply do the following:
+```
+dd if=/dev/zero of=/swap bs=1M count=2048
+chmod 0600 /swap
+mkswap /swap
+swapon /swap
+```
+You can now check swap status using `free -h`. To automatically mount this swap file on boot, add the following line at the end of your `/etc/fstab` file:
+```
+/swap none swap sw 0 0
+```
+
+## Firewall
+Again, as mentioned in the excellent guide, all ports except tcp/22 are blocked by default. If you'd like these opening, in your Oracle account go to Networking > Virtual Cloud Networks > vcn-creationdate-time > Security Lists > Default Security List > Ingress Rules.
+Here, delete the 3 existing rules (if you'd like to respond to ICMP packets), then create a new rule with the following details:
+
+* Stateless: No
+* Source Type: CIDR
+* Source CIDR: 0.0.0.0/0
+* IP Protocol: All Protocols
+
+Once saved, you should be able to access anything you're hosting as you'd expect.
+
+## Changing Shells
+Lastly, I quite like the fish shell (hate all you want), but the `chsh` utility is missing so to change your shell you need to manually edit your `/etc/passwd` file, replacing `/bin/ash` with `/usr/bin/fish` or whatever other shell you'd like to use.
+
+## Supporting Ansible
+I'm looking at managing my servers with ansible, the requirements here are somewhat simple, all you need is a python binary which can be installed via:
+```
+apk add python3
+```
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