I'm on a fresh Centos 8 install and have tried to use yum for the first time (on this machine). I get the following for any attempt to install or update anything:
yum update
CentOS-8 - AppStream 0.0 B/s | 0 B 00:00
Failed to download metadata for repo 'AppStream'
Error: Failed to download metadata for repo 'AppStream'
Port 80 is open although nmap reports it as closed presumably because I haven't yet installed apache. To be double sure I have added port 80 to firewalld which is confirmed:
firewall-cmd --list-ports
25/tcp 80/tcp
I have tried various advice like yum clean and clearing the yum cache but nothing helps.
This is what is in the dnf.log:
2020-03-30T19:33:01Z INFO --- logging initialized ---
2020-03-30T19:33:01Z DDEBUG timer: config: 4 ms
2020-03-30T19:33:01Z DEBUG Loaded plugins: builddep, changelog, config-manager, copr, debug, debuginfo-install, download, generate_completion_cache, needs-restarting, playground, repoclosure, repodiff, repograph, repomanage, reposync
2020-03-30T19:33:01Z DEBUG DNF version: 4.2.7
2020-03-30T19:33:01Z DDEBUG Command: yum install httpd
2020-03-30T19:33:01Z DDEBUG Installroot: /
2020-03-30T19:33:01Z DDEBUG Releasever: 8
2020-03-30T19:33:01Z DEBUG cachedir: /var/cache/dnf
2020-03-30T19:33:01Z DDEBUG Base command: install
2020-03-30T19:33:01Z DDEBUG Extra commands: ['install', 'httpd']
2020-03-30T19:33:01Z DEBUG repo: downloading from remote: AppStream
2020-03-30T19:33:02Z DEBUG error: Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org] (http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock).
2020-03-30T19:33:02Z DEBUG Cannot download 'http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock': Cannot prepare internal mirrorlist: Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org].
2020-03-30T19:33:02Z ERROR Failed to download metadata for repo 'AppStream'
2020-03-30T19:33:02Z DDEBUG Cleaning up.
2020-03-30T19:33:02Z SUBDEBUG
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 552, in load
ret = self._repo.load()
File "/usr/lib64/python3.6/site-packages/libdnf/repo.py", line 394, in load
return _repo.Repo_load(self)
RuntimeError: Failed to download metadata for repo 'AppStream'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 65, in main
return _main(base, args, cli_class, option_parser_class)
File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 98, in _main
return cli_run(cli, base)
File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 114, in cli_run
cli.run()
File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 1134, in run
self._process_demands()
File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 832, in _process_demands
load_available_repos=self.demands.available_repos)
File "/usr/lib/python3.6/site-packages/dnf/base.py", line 406, in fill_sack
self._add_repo_to_sack(r)
File "/usr/lib/python3.6/site-packages/dnf/base.py", line 136, in _add_repo_to_sack
repo.load()
File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 558, in load
raise dnf.exceptions.RepoError(str(e))
dnf.exceptions.RepoError: Failed to download metadata for repo 'AppStream'
2020-03-30T19:33:02Z CRITICAL Error: Failed to download metadata for repo 'AppStream'
Best Answer
Apparently not the problem here, but if you have pinned yourself to CentOS 8.1.1911 you will get the same error until you re-point your /etc/yum.repos.d/ repositories at http://vault.centos.org instead of http://mirror.centos.org