61 lines
2.3 KiB
Markdown
61 lines
2.3 KiB
Markdown
## Administering an rpm-ostree based system
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At the moment, there are four primary commands to be familiar with on
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an `rpm-ostree` based system. Also remember that in a Project Atomic
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system, the `atomic host` command (from the
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[Atomic command](https://github.com/projectatomic/atomic/)) is an
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alias for `rpm-ostree`. The author tends to use the former on client
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systems, and the latter on compose servers.
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```
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# atomic host status
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```
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Will show you your deployments, in the order in which they will appear
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in the bootloader. The `*` shows the currently booted deployment.
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```
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# atomic host upgrade
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```
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Will perform a system upgrade, creating a *new* chroot, and set it as
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the default for the next boot. You should use `systemctl reboot`
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shortly afterwards.
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```
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# atomic host rollback
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```
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By default, the `atomic upgrade` will keep at most two bootable
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"deployments", though the underlying technology supports more.
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```
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# atomic host deploy <version>
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```
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This command makes use of the server-side history feature of OSTree.
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It will search the history of the current branch for a commit with the
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specified version, and deploy it. This can be used in scripts to
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ensure consistent updates. For example, if the upstream OS vendor
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provides an update online, you might not want to deploy it until
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you've tested it. This helps ensure that when you upgrade, you are
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getting exactly what you asked for.
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## Filesystem layout
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The only writable directories are `/etc` and `/var`. In particular,
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`/usr` has a read-only bind mount at all times. Any data in `/var` is
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never touched, and is shared across upgrades.
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At upgrade time, the process takes the *new default* `/etc`, and adds
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your changes on top. This means that upgrades will receive new
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default files in `/etc`, which is quite a critical feature.
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For more information, see
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[OSTree: Adapting](https://ostree.readthedocs.io/en/latest/manual/adapting-existing/).
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## Operating system changes
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* The RPM database is stored in `/usr/share/rpm`, and is immutable.
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* A package [nss-altfiles](https://github.com/aperezdc/nss-altfiles)
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is required, and the system password database is stored in
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`/usr/lib/passwd`. Similar for the group database. This might
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change in the future; see
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[this issue](https://github.com/projectatomic/rpm-ostree/issues/49).
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