Michael Stapelberg
f68947708b
This makes using gokr-rsync via SSH (command) easier: You won’t need to specify --rsync-path=gokr-rsync anymore.
137 lines
3.8 KiB
Markdown
137 lines
3.8 KiB
Markdown
---
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title: "Permanent data backup with the gokrazy rsync"
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menuTitle: "Data backup with rsync"
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weight: 80
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---
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I like to periodically back up all scans from my [scan2drive
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appliance](/packages/showcase/) to my PC. The PC is backed up as well, so that
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automatically distributes my scans to multiple machines in case one of them
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fails.
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A convenient way to set up an efficient partial or full backup of a gokrazy
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device’s permanent data partition is to use [the gokrazy rsync
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daemon](https://github.com/gokrazy/rsync). This article walks you through how I
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have set up my backup, but many variants are possible to cater to different
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requirements.
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(You don’t typically need backups of your gokrazy device’s root partition
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because it can be built reproducibly any time using Go.)
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## Step 1. Install the gokrazy rsync daemon {#install}
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Add the gokrazy rsync implementation `gokr-rsync` to your gokrazy instance:
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```bash
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gok add github.com/gokrazy/rsync/cmd/gokr-rsync
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```
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## Step 2. Configure the gokrazy rsync daemon {#configure}
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Open your gokrazy instance’s `config.json` in your editor:
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```bash
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gok edit
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```
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Configure [Package config: Command-line flags](/userguide/package-config/#flags) and [Package config: Extra files](/userguide/package-config/#extrafiles):
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{{< highlight json "hl_lines=11-21" >}}
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{
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"Hostname": "backedup",
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"Packages": [
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"github.com/gokrazy/fbstatus",
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"github.com/gokrazy/hello",
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"github.com/gokrazy/serial-busybox",
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"github.com/gokrazy/breakglass",
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"github.com/gokrazy/rsync/cmd/gokr-rsync"
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],
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"PackageConfig": {
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"github.com/gokrazy/rsync/cmd/gokr-rsync": {
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"Basename": "rsync",
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"CommandLineFlags": [
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"--daemon",
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"--gokr.config=/etc/gokr-rsyncd.toml"
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],
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"ExtraFilePaths": {
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"/etc/gokr-rsyncd.toml": "gokr-rsyncd.toml",
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"/etc/gokr-rsyncd.authorized_keys": "gokr-rsyncd.authorized_keys"
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}
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}
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}
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}
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{{< /highlight >}}
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In the daemon config file, configure an authorized SSH listener and which
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rsync modules to serve:
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```bash
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cat > ~/gokrazy/hello/gokr-rsyncd.toml <<'EOT'
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dont_namespace = true
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[[listener]]
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[listener.authorized_ssh]
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address = "scan2drive.lan:22873"
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authorized_keys = "/etc/gokr-rsyncd.authorized_keys"
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[[module]]
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name = "scans"
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path = "/perm/scans"
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EOT
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```
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Finally, create the authorized keys file that determines who can access the rsync daemon:
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```bash
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cat > ~/gokrazy/hello/gokr-rsyncd.authorized_keys <<'EOT'
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ssh-ed25519 […] michael@midna
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EOT
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```
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Then, deploy as usual:
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```bash
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gok update
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```
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## Step 3. Configure SSH from the backup machine {#ssh}
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On your PC (not the gokrazy instance), add an SSH configuration stanza to your
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`~/.ssh/config` to configure the custom port (22873 for ssh+rsync) and which
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passwordless identity file to use (for the [cron job in step 4](#cron)):
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```text
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Host scan2drive-backup
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Hostname scan2drive.lan
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Port 22873
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IdentityFile ~/.ssh/id_ed25519_scan2drivebackup
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```
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Now you should be able to run rsync via SSH as usual:
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```bash
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rsync -av -e ssh rsync://scan2drive-backup/scans/ ~/scan2drive-backup/
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```
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## Step 4. Configure a daily cron job {#cron}
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First, install [the `rsync-prom` tool](https://github.com/stapelberg/rsyncprom)
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to monitor your periodic transfer with [Prometheus](https://prometheus.io/):
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```bash
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go install github.com/stapelberg/rsyncprom/cmd/rsync-prom@latest
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```
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Then wrap the above rsync command in an rsync-prom invocation in a shell script called `scan2drive-backup-sync.sh`:
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```bash
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#!/bin/sh
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SSH_AUTH_SOCK= ~/go/bin/rsync-prom --instance="scan2drive@midna" \
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rsync -av -e ssh rsync://scan2drive-backup/scans/ ~/scan2drive-backup/
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```
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Finally, run `crontab -e` and run the script at your convenience, like so:
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```
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30 07 * * * /home/michael/scan2drive-backup-sync.sh
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```
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