OSTree Manual |
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First, the most basic model OSTree supports is one where it
replicates pre-generated filesystem trees from a server over
HTTP, tracking exactly one ref, which is stored in the .origin
file for the deployment.
The command ostree admin upgrade implements
this.
To begin a simple upgrade, OSTree fetches the contents of the
ref from the remote server. Suppose we're tracking a ref named
gnome-ostree/buildmaster/x86_64-runtime
.
OSTree fetches the URL
http://
,
which contains a SHA256 checksum. This determines the tree to
deploy, and example.com
/repo/refs/gnome-ostree/buildmaster/x86_64-runtime/etc
will be
merged from currently booted tree.
If we do not have this commit, then, then we perform a pull
process. At present (without static deltas), this involves
quite simply just fetching each individual object that we do not
have, asynchronously. Put in other words, we only download
changed files (zlib-compressed). Each object has its checksum
validated and is stored in /ostree/repo/objects/
.
Once the pull is complete, we have all the objects locally we need to perform a deployment.