Recently I had explored upgrading CentOS 7 to CentOS 8 and during the process, I encountered the error: Failed to synchronize cache for repo ‘appstream’. Below is the complete error:
Failed to synchronize cache for repo 'baseos', ignoring this repo. Failed to synchronize cache for repo 'appstream', ignoring this repo.
Output from the
/var/log/dnf.log for more DEBUG information:
2022-02-15T10:09:08Z DEBUG repo: downloading from remote: appstream 2022-02-15T10:09:08Z DEBUG Cannot download 'http://mirror.centos.org/centos/8/AppStream/x86_64/os/': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried. 2022-02-15T10:09:08Z DEBUG repo: downloading from remote: extras 2022-02-15T10:09:08Z DEBUG not found other for: CentOS Linux 8 - Extras 2022-02-15T10:09:08Z DEBUG not found modules for: CentOS Linux 8 - Extras 2022-02-15T10:09:08Z DEBUG not found deltainfo for: CentOS Linux 8 - Extras 2022-02-15T10:09:08Z DEBUG not found updateinfo for: CentOS Linux 8 - Extras 2022-02-15T10:09:08Z DEBUG extras: using metadata from Fri 10 Dec 2021 06:26:25 PM IST. 2022-02-15T10:09:08Z WARNING Failed to synchronize cache for repo 'baseos', ignoring this repo. 2022-02-15T10:09:08Z WARNING Failed to synchronize cache for repo 'appstream', ignoring this repo.
Looking at the error message, I thought the issue might be because of the internet connection. However, the internet connection and DNS worked just fine as shown below.
[root@upgrade-centos log]# ping google.com PING google.com (22.214.171.124) 56(84) bytes of data. 64 bytes from del03s13-in-f14.1e100.net (126.96.36.199): icmp_seq=1 ttl=115 time=44.10 ms ^C --- google.com ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 44.971/44.971/44.971/0.000 ms
So how did I fix the issue? Here it is.
How to fix Failed to synchronize cache for repo appstream
There could be multiple reasons for this issue. The most common ones are:
- Incorrect date and time settings
dnfcache available or expired
- CentOS baseURL
How to fix Incorrect date and time settings
timedatectlcommand is a new utility tool in CentOS 7/8. It is a replacement for old traditional
date command used in
sysvinit daemon-based Linux distributions.
Find the current date and time of your system. Make sure it is correct with the proper time zone.
[root@upgrade-centos ~]# timedatectl Local time: Tue 2022-02-15 11:24:25 UTC Universal time: Tue 2022-02-15 11:24:25 UTC RTC time: Tue 2022-02-15 11:24:25 Time zone: UTC (UTC, +0000) System clock synchronized: no NTP service: active RTC in local TZ: no
Set to your timezone
[root@upgrade-centos ~]# timedatectl set-timezone "Asia/Kolkata" [root@upgrade-centos ~]# date Tue Feb 15 16:58:57 IST 2022
How to clear Old/expired dnf cache
Here is an article to clean each kind of cache. To clean all of it, run the below command:
[root@upgrade-centos ~]# dnf clean all [root@upgrade-centos ~]# rm -rf /var/cache/dnf
How to change CentOS baseURL from mirror.centos.org to vault.centos.org
CentOS Linux 8 had reached the End Of Life (EOL) on December 31st, 2021. It means that CentOS 8 will no longer receive development resources from the official CentOS project. After Dec 31st, 2021, if you need to update your CentOS, you need to change the mirrors to vault.centos.org where they will be archived permanently. Alternatively, you may want to upgrade to CentOS Stream or migrate from CentOS to Rocky Linux.
Go to the
[root@autocontroller ~]# cd /etc/yum.repos.d/
Run the below commands
[root@autocontroller ~]# sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
[root@autocontroller ~]# sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*
[root@autocontroller ~]# dnf update
Comments Leave a Comment
It’s work thanks you so much
Works. Thank you!
thanks is working
Nice! it works as long as i dont do dnf update!
that actually broke my last system so i run the two “sed” commands and just leave it at that
Thank you, it helped me update my system (installed in late October 2021, so just a few months before CentOS 8 went EOL:ed). People joke about which year Linux Desktop will become reality, but I find that Linux Server is complicated as it is with these upgrades, changed paths and whats not.
You are a lifesaver Ramya! Thank you!
It broke my system
AWESOME! Fixed Issue! Thank you!
It has broke my system.
This really saved my life 🙂
Helped me a lot, thank you.
Now I get an error saying “Cannot find a valid baseurl for repo: AppStream”
anybody else with the same issue?
Thank you so much bro!
great thank you
Super! Than you!
thanks man ! it’s working … your content is appreciated
it’s work now. thank you alot.
Very helpful! Thank you
it was helpful
Very usefull thank you so much