Replicating a base immutable OS, then using Docker for applications
meshes together two different tools with different tradeoffs.
-[xdg-app](https://github.com/alexlarsson/xdg-app) uses OSTree
+[xdg-app](https://github.com/alexlarsson/xdg-app) uses OSTree
for desktop application containers.
[GNOME Continuous](https://wiki.gnome.org/Projects/GnomeContinuous) is
New! See the docs online at [Read The Docs (OSTree)](https://ostree.readthedocs.org/en/latest/ )
Some more information is available on the old wiki page:
-https://wiki.gnome.org/Projects/OSTree
+<https://wiki.gnome.org/Projects/OSTree>
Contributing
------------
You can:
- 1. Send mail to ostree-list@gnome.org, with the patch attached
- 1. Submit a pull request against https://github.com/GNOME/ostree
- 1. Attach them to https://bugzilla.gnome.org/
+ 1. Send mail to <ostree-list@gnome.org>, with the patch attached
+ 1. Submit a pull request against <https://github.com/GNOME/ostree>
+ 1. Attach them to <https://bugzilla.gnome.org/>
-Please look at "git log" and match the commit log style.
+Please look at `git log` and match the commit log style.
Running the test suite
----------------------
-Currently, ostree uses https://wiki.gnome.org/GnomeGoals/InstalledTests
-To run just ostree's tests:
+Currently, OSTree uses <https://wiki.gnome.org/GnomeGoals/InstalledTests>
+
+To run just OSTree's tests:
./configure ... --enable-installed-tests
gnome-desktop-testing-runner -p 0 ostree/
myfunc (...)
{
gboolean ret = FALSE;
-
+
/* some code */
-
+
/* some more code */
-
+
if (condition)
return FALSE;
-
+
/* some more code */
-
+
ret = TRUE;
out:
return ret;
{
/* deeply nested code */
}
-
+
/* more nested code */
}
}
}
Instead do this:
-
+
static gboolean
helperfunc (..., GError **error)
{
{
/* deeply nested code */
}
-
+
/* more nested code */
-
+
return ret;
}
-
+
while (condition)
{
/* some code */
if (!condition)
continue;
-
+
for (i = 0; i < somevalue; i++)
{
if (!helperfunc (..., i, error))
goto out;
}
}
-
removing anything, we can make the major optimization of reusing
our existing filesystem tree, and merely
*layering* the composed filesystem tree of
-these new packages on top. A command like this:
+these new packages on top. A command like this:
```
ostree commit -b osname/releasename/description
deployment. The command `ostree admin upgrade`
implements this.
-o begin a simple upgrade, OSTree fetches the contents of the ref from
+To begin a simple upgrade, OSTree fetches the contents of the ref from
the remote server. Suppose we're tracking a ref named
`exampleos/buildmaster/x86_64-runtime`. OSTree fetches the URL
`http://$example.com/repo/refs/exampleos/buildmaster/x86_64-runtime`,
Given a commit to deploy, OSTree first allocates a directory for
it. This is of the form `/boot/loader/entries/ostree-$osname-$checksum.$serial.conf`.
-he $serial is normally 0, but if a
+The `$serial` is normally 0, but if a
given commit is deployed more than once, it will be incremented.
his is supported because the previous deployment may have
-configuration in `/etc`
-hat we do not want to use or overwrite.
+configuration in `/etc` that we do not want to use or overwrite.
Now that we have a deployment directory, a 3-way merge is
performed between the (by default) currently booted deployment's
configuration is untouched. We want to add this deployment o the
"deployment list".
-To support a more general case, OSTree supports atomic ransitioning
+To support a more general case, OSTree supports atomic transitioning
between arbitrary sets of deployments, with the restriction that the
currently booted deployment must always be in the new set. In the
normal case, we have exactly one deployment, which is the booted one,
at a time; each deployment is intended to be a target for
`chroot()` or equivalent.
-### "osname": Group of deployments that share /var</title>
+### "osname": Group of deployments that share /var
Each deployment is grouped in exactly one "osname". From above, you
can see that an osname is physically represented in the
## Static deltas
-OSTree itself was originally focused on a continous delivery model, where
+OSTree itself was originally focused on a continuous delivery model, where
client systems are expected to update regularly. However, many OS vendors
would like to supply content that's updated e.g. once a month or less often.
more efficiently download a commit object from scratch.
Effectively, we're spending server-side storage (and one-time compute
-cost), and gaining efficiency in client network bandwith.
+cost), and gaining efficiency in client network bandwidth.
## Static delta repository layout
A delta is named `$(mbase64 $from)-$(mbase64 $to)`, for example
`GpTyZaVut2jXFPWnO4LJiKEdRTvOw_mFUCtIKW1NIX0-L8f+VVDkEBKNc1Ncd+mDUrSVR4EyybQGCkuKtkDnTwk`,
-which in sha256 format is
+which in SHA256 format is
`1a94f265a56eb768d714f5a73b82c988a11d453bcec3f985502b48296d4d217d-2fc7fe5550e410128d73535c77e98352b495478132c9b4060a4b8ab640e74f09`.
Finally, the actual content can be found in
- delta generation timestamp
- the new commit object
- An array of recursive deltas to apply
- - An array of per-part metadata, including total object sizes (compressed and uncompressed),
+ - An array of per-part metadata, including total object sizes (compressed and uncompressed),
- An array of fallback objects
Let's define a delta part, then return to discuss details:
[bsdiff](https://github.com/mendsley/bsdiff) that most notably works
well on executable code.
-The current delta compiler scans for files with maching basenamesin
+The current delta compiler scans for files with matching basenames in
each commit that have a similar size, and attempts a bsdiff between
them. (It would make sense later to have a build system provide a
hint for this - for example, files within a same package).
A generated bsdiff is included in the payload blob, and applying it is
an instruction.
-
+
## Fallback objects
It's possible for there to be large-ish files which might be resistant
# OSTree Overview
-## Introduction
+## Introduction
OSTree an upgrade system for Linux-based operating systems that
performs atomic upgrades of complete filesystem trees. It is
bootloader configuration, management of
`/etc`, and other functions to perform an
upgrade beyond just replicating files.
-
+
You can use OSTree standalone in the pure replication model,
but another approach is to add a package manager on top,
thus creating a hybrid tree/package system.
separate mechanism to install applications, stored in `/var` if they're system global, or
`/home` for per-user
application installation. An example application mechanism is
-http://docker.io/
+<http://docker.io/>
However, it is entirely possible to use OSTree underneath a
package system, where the contents of `/usr` are computed on the client.
one where content files are just stored as regular files; it's
designed to be the source of a "hardlink farm", where each operating
system checkout is merely links into it. If you want to store files
-owned by e.g. root in this mode, you must run OSTree as root.
+owned by e.g. root in this mode, you must run OSTree as root.
The `bare-user` is a later addition that is like `bare` in that files
are unpacked, but it can (and should generally) be created as
non-root. In this mode, extended metadata such as owner uid, gid, and
-extended attributes are stored but not actually applied.
+extended attributes are stored but not actually applied.
The `bare-user` mode is useful for build systems that run as non-root
but want to generate root-owned content, as well as non-root container
systems.
projects / ostree.git / commitdiff