# How to create a public mirror for AlmaLinux

Mirrors are extremely important to provide a fast and reliable infrastructure, and we are very grateful to people and organizations that help us with this. The current list of public mirrors can be found on the mirrors.almalinux.org (opens new window) website.

You can create a public AlmaLinux mirror in a few easy steps:

Make sure that you have enough free space: 500GB per major version is the suggested minimum. As there are currently two supported major versions (8 and 9) the recommended minimum storage space is 1TB.

Optional but recommended

Use updated version of rsync with xxhash support.

xxhash provides a superior hashing algorithm to rsync which lightens the load on the source and destination servers. We maintain an up-to-date version of rsync in the AlmaLinux backports repository. To use this repository on EL8 and EL9 distros:
```
curl http://repo.almalinux.org/backports/almalinux-backports-rsync.repo --output /etc/yum.repos.d/almalinux-backports-rsync.repo
yum -y update rsync
```
You can verify that you have the expected version of rsync and xxhash support as follows:
```
$ rsync --version |grep xxhash
xxh128 xxh3 xxh64 (xxhash) md5 md4 sha1 none
```

Synchronize with the official AlmaLinux mirror via rsync:
```
/usr/bin/rsync -avSH --exclude='.~tmp~' --delete-delay --delay-updates rsync://rsync.repo.almalinux.org/almalinux/ /almalinux/dir/on/your/server/
```
- The official tier0 rsync mirrors are in Atlanta, GA, USA, and Seattle, WA, USA. We use geolocation-based DNS steering to send your traffic to the closest tier0 mirror. If your mirror is not in the United States or you are otherwise seeing suboptimal speed from this source we recommend performing the initial sync from a mirror close to you. Make sure that your cron syncs from the official mirror, however.

Create a cron task to sync it periodically (we recommend updating the mirror every 3 hours):

0 */3 * * * sleep $(((RANDOM\%3500)+1)) && /usr/bin/flock -n /var/run/almalinux_rsync.lock -c "/usr/bin/rsync -avSH --exclude='.~tmp~' --delete-delay --delay-updates rsync://rsync.repo.almalinux.org/almalinux/ /almalinux/dir/on/your/server/"

Ensure the accuracy of city, longitude, and latitude data for your mirror IP(s) with IPinfo at https://ipinfo.io (opens new window). Submit a correction request (opens new window) with accurate city data if the information is incorrect.

Our mirrorlist URL tries to serve the best mirror to a client based on IPinfo geolocation data so having accurate IPinfo data ensures the best possible experience for users.
Join the mirror-announce (opens new window) mailing list to receive important mirror-related updates from the AlmaLinux team.

You may also consider joining the mirror (opens new window) mailing list for general discussion/help related to mirrors.

We recommend joining the mirrors channel on Mattermost (opens new window) for any questions as well as updates from our team that impact mirror hosts in a live interactive format.

Fork the github.com/AlmaLinux/mirrors (opens new window) repository and create a pull request that will add a YAML file describing your mirror to the mirrors.d directory. You can use the official AlmaLinux repo file (opens new window) as an example. Your mirror does not have to provide all the protocols that our main mirror provides, but either HTTP or HTTPS is required. Format of a mirror's config is described below. Also, you can validate your config to use some JSON online validator using that JSON schema (opens new window) and converting your config to JSON.

---
name: <domain name of a mirror, e.g. almalinux.mirror.link>
cloud_type: <azure|aws. It'll be required if a mirror is located in AWS/Azure cloud>
address:
  http: <http URL to a mirror, e.g. http://almalinux.mirror.link/almalinux>
  https: <https URL to a mirror, e.g. https://almalinux.mirror.link/almalinux>
  rsync: <rsync URL to a mirror, e.g. rsync://almalinux.mirror.link/almalinux>
  ftp: <ftp URL to a mirror, e.g. ftp://almalinux.mirror.link/almalinux>
update_frequency: <update frequency of a mirror, e.g. 1h>
sponsor: <Name of a mirror's sponsor/holder, e.g. Some company name>
sponsor_url: <URL of a mirror's sponsor/holder, e.g. http://some.company.name>
email: <e-mail of a mirror's sponsor/holder, e.g. admin@some.company.name>
geolocation:
  continent: <name of a continent, e.g. North America; this field is not mandatory>
  country: <two-letter name of a country, e.g. US>
  state_province: <name of a province, e.g. New York>
  city: <name of a city, e.g. New York>
private: <true|false. A mirror is available in some local network if the param is true>
monopoly: <true|false. The mirrors list contains only this private mirror for a suitable client if param is true>
# The list will be required if a mirror is local or cloud.
# It contains subnets behind which located a private mirror.
# Also, it can be string and contains URL which returns json list with subnets
subnets:
  - <network mask>
# That parameter can specify ASN which is maintained by a mirror is located in cloud
# It can be number or list of numbers:
# asn: 40162
# or
# asn:
#   - 41222
#   - 91213
# or
# asn: [12345, 98765]
asn: <ASN number or list of ASN numbers, see https://en.wikipedia.org/wiki/Autonomous_system_(Internet)>.
# The list will be required if a mirror is located in Azure/AWS cloud
cloud_regions:
  - <cloud_region of Azure/AWS, e.g. australiacentral2>
...

You could find more information about creating a pull request in GitHub documentation (opens new window). After reviewing the pull request your mirror will be published at the mirrors.almalinux.org (opens new window) page and will be added to the mirrorlists that dnf package manager works with.

All mirror hosts are eligible for membership to the AlmaLinux OS Foundation. Make sure you submit your application for membership (opens new window)!

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