As explained on Debian's documentation on this subject:
> Push mirroring is a form of mirroring that minimizes the time it takes > for changes to the main archive to reach mirrors. The server mirror uses > a triggering mechanism to immediately inform the client mirror that it > needs to be updated. > > Push mirroring takes a little more effort to set up since the maintainers > of the upstream and downstream mirror must exchange information. The > benefit is that the upstream mirror initiates the mirror process immediately > after its archive has been updated. This allows changes to the archive to > propagate extremely quickly.
So instead of relying on cron jobs to keep things in sync, mirrors can be asked to sync when it is necessary. SSH is usually used, however we can offer HTTP triggers if preferred.
Your mirror should have previously been set up to use cron jobs and mirroring scripts. Such scripts can be found here.
We recommend that you create an ubuntu user and grant it permissions to the directory where your mirror is stored. Then place the keys below (or from whichever mirror you are syncing from) into that user's authorized_keys file.
When the upstream mirror connects as the ubuntu user to your mirror, it will run the script and background the process. Meanwhile the rsync command called by the script, will connect to the upstream mirror and sync any changes as needed.
When this setup has been completed, please let us know and we'll set up the necessary trigger commands on our end.
If the command is not run in the background, you can try redirecting stdin, stdout and stderr to /dev/null, i.e. use the following command :
command="~/archive-sync </dev/null >/dev/null 2>/dev/null &"
These are the SSH keys used for triggering archive and releases mirrors respectively. Please be sure to change the command= option to the location of your mirroring script and do not remove the backgrounding character (&) after it.
The keys below are for mirrors pushed by Canonical-only, these mirrors should be syncing from rsync.archive.ubuntu.com (for packages) and rsync.releases.ubuntu.com (for CD release images). Connections from Canonical will be originating from the IP address: 220.127.116.11 for archive, and 18.104.22.168 for releases - so please ensure that your firewalls allow this.
For authenticity; these keys are signed by Jonathan Davies with the key ID 0x5AA3DF71.
If you are not being pushed by Canonical, please contact the mirror administrator of the mirror you're being pushed from for their keys and be sure to have your sync source set to their mirror.
Archive trigger key
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Ubuntu Archive trigger SSH key for Canonical. SSH key fingerprint: c8:ea:0f:db:86:da:64:86:de:76:64:b8:84:33:4b:23 no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,command="~/archive-sync &",from="22.214.171.124" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAt8xHRbCVFT3Uw/B+TavIlDYRoLMxOKlN3HnBeniFUJTto5Im52FbT3ODfMszz5/BIAnXBf1baWDljHErx4huohh9MxyovZ0h8GYCmMy7dZzsrV5eYhLXd2idCOKIl6gr0BTgTlJOKOgVEoZ2YtiU9MnNzRk3gkBeCMDJrnQOCC8Sko0F0RUJnrzLXOdtvDfNu7Ff+tRNb4PwrU3inbm2YJRnOoZI9vIsv/9DwsMm9d+YIIOz/7y5jLGhZ34nXzhmI6cJO92+Ve5ubhbbpKUFQAh2L1PP6A+I7jHvoWHToSaZlt+DCN4Kg+JlZuf2FXk8MeHkEc6qWWHQTFF8/ArKew== archvsync@syowa -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAEBAgAGBQJLjEQpAAoJEFUBJbxao99xruMQAKHEjI2KMdZueZSK1qXO2eVf ianGvfiYmUhq3yM6augScQbr97CoUY1cMTa64cz+wpxy1inGmvFLrs6m36PaNXFR JAaFfR57oIozTpiZq6vl/Skme/6t4OKX0ZQVo/0YnnlGUoLD2RZE3XaP5x8Y20FB 0cENvZGObGJEcC3reH/WxhiSOwmOI0re3W9krv6jYm1qSBFnLTASecNJM3jtvmFM 3Qpvhst4WZRRg/jDaozIgZLooJZF1wCJEMKAEWbAS9pYCwABZe+p8lIfpEHbRIE1 Smq/Wce2BQv6oxcxvchMo8RXxJzurCSDzBQhFUpjjtJyG7wU1C+uMOGrgCBCJe9z Fe4QOxBOBhkBp3CSBoxqFkIwsajiF5okM6nJZTMxYxRGqaLMNPYUYzMJ7qVdJXOR XopYqdUtFXqNrda26duL+WbDEQY0VZD3j8kCbKlysgK3R9p2pUZpbPC8tpHwea96 TVxQKn8X+FS+4qSURpWt3m5g/tsx9WfXK1RZO69j7AzcrLvq1SWXASWdoLjwWyVo lEuAJBkKyshV1kr7oHTeIzx7r4O4VQFpNpwjLs7kqhVqeA3ilul2/uCa6WdOIPA5 BHCVNVvthFLcW7CP5Y03vn5y/qY5m/34FhaRFl+Y1QfJG0WbQ5uPkR4aiSHL6kL5 riOyPx8It1Dnje2b00Lb =Qerg -----END PGP SIGNATURE-----
Releases trigger key
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Ubuntu Releases trigger SSH key for Canonical. SSH key fingerprint: ff:79:41:eb:c7:7d:00:d4:78:34:28:d1:d2:f0:ae:90 no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,command="~/releases-sync &",from="126.96.36.199" ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA7l6nWM6Z2KfR4KmwF29Fv9nAgTLwHM5H/TWhinl7DZDG+Jn+TC9kll3cuyGByhwh/mNTwbyvsyiDSXFtbglowQoPSW4rhOEVy6s+/lDjDBGTDsgk8wyBqlNJRlppODsl+kqX0IqAIc3XJ9luDl894tD5rxhiXzqXL3c8r8CuhPkGdUCCMbWU4OUAIjIAs8DClYzjrAZ54IVbk5gTjDYUtlSLNXjm1rZ788h65waKBn4/LV+8nEaFIPA9FxPZI6VLmKGO/RQqZrLPNKOzotmkofV1jV2OmQNHzIwu2seV6HGYqZc3U9jE2+Eat86C6IMYS7KPxVoQd6AnHjRMlhyb6Q== archvsync@syowa -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQIcBAEBAgAGBQJLjEReAAoJEFUBJbxao99xRmYP/2XFhomblK0i/BXc9h9bso95 IJ2566dYewJOlcwUmSUXxXylgAIXfXeQPHgPtbrvwo6E1RnsYpVGZhJB+n07OxF2 BsK8OQsOanf3+UvNoZho7J0jDQHJHom+DFJ9nxcb7IDg8BNN2sUrgx+Mpn2T+39c OJzuQy888HarWLqcmbO6WpZ3yrhjUomb0uuJQKJatYyAQCW8qnZSe0OBHv4bytko uo/zBKcE7SY4i6bk1T6uNghkr4zVBGMSyyZJ4cF3AXyM9a/VA2jH/PN/SE8Kd4qM XszEfqekHLwfeoeekadfIy3QRLx7gKu4fXIIML2Pq8m+XzK0niJIFj6821FbwnY1 g9OyJTTDAOjgBbfRON2It7wjjWkup13hb5KzaZqoQPS2P8PJDkQPFvOSnBXU0BCE CgY29xFgW5RxNX0+suGYRi5ICIuoo+J82QBfoHtlp9Uv1aA1PJpaF1ZHdrS6ZqFn PzR9NogrUuCPpiTw8RbYLxDlGpOkru02pHlKehxn2YHGitMFONaMzVG+gauS5wXL qZcGSEx+xHqLYDAJZ8b6Tu7FmTv+bhXii4y9M58oFi5ORw9Yr7wWKsulzfSqKMO+ 1ducvCV1NXu4qaWHREcTV1Wx5bkQPSRp6ukkf+UEBVDWpWUuI4fdxWuUUNp+eCqj kfvsD5X7S9OcpyL+l0EV =yoRX -----END PGP SIGNATURE-----
While SSH triggers above are the preferred trigger method, it is also possible for the master Ubuntu archive to send HTTP triggers. HTTP triggers can be nearly any format, for example:
The first example uses usernames and (long random) passwords to a trigger destination, and would decide which component to begin syncing based on the authenticated username. The second example places the component name and (long random) UUID in the path itself. Treat these URLs as sensitive, to avoid outside users triggering unnecessary syncs.
It is up to the mirror administrator to build logic into the HTTP endpoint which authenticates the master Ubuntu archive and begins a sync. This logic varies wildly based on your specific platform. Output format is undefined; the master simply loads the URL and moves on without examining the output.