Centos 7에러

깔자마자 yum update 입력

에러 1

Loaded plugins: fastestmirror, langpacks

Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was

14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"

 One of the configured repositories failed (Unknown),

 and yum doesn't have enough cached data to continue. At this point the only

 safe thing yum can do is fail. There are a few ways to work "fix" this:

     1. Contact the upstream for the repository and get them to fix the problem.

     2. Reconfigure the baseurl/etc. for the repository, to point to a working

        upstream. This is most often useful if you are using a newer

        distribution release than is supported by the repository (and the

        packages for the previous distribution release still work).

     3. Run the command with the repository temporarily disabled

            yum --disablerepo=<repoid> ...

     4. Disable the repository permanently, so yum won't use it by default. Yum

        will then just ignore the repository until you permanently enable it

        again or use --enablerepo for temporary usage:

            yum-config-manager --disable <repoid>

        or

            subscription-manager repos --disable=<repoid>

     5. Configure the failing repository to be skipped, if it is unavailable.

        Note that yum will try to contact the repo. when it runs most commands,

        so will have to try and fail each time (and thus. yum will be be much

        slower). If it is a very temporary problem though, this is often a nice

        compromise:

            yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true

Cannot find a valid baseurl for repo: base/7/x86_64

==> 네트워크 연결이 안되어있는 것, 네트워크 연결하면 됨

에러2

Another app is currently holding the yum lock; waiting for it to exit...

  The other application is: PackageKit

    Memory : 111 M RSS (1.5 GB VSZ)

    Started: Wed Oct 25 23:06:50 2017 - 01:16 ago

    State  : Sleeping, pid: 12815

==> yum 12815라고 입력하니까

bash: kill: (12815) - No such process

라고 뜬다.

그리고 다시 yum udpate하니까 되긴 한다.

3. 관리 디렉터리를 잠글 수 없습니다 다른 프로세스가 사용하고 있지 않습니까?

reboot 하면 해결됨