RHEL7 on EC2 のyum upadteエラー

EC2のRHEL7インスタンスでyum upadte2回目でエラーが発生します。

```bash
# sudo yum update
Loaded plugins: amazon-id, rhui-lb
rhui-REGION-client-config-server-7                               | 2.9 kB  00:00:00
https://rhui2-cds01.ap-northeast-1.aws.ce.redhat.com/pulp/repos//content/dist/rhel/rhui/server/7/7Server/x86_64/optional/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.
https://rhui2-cds02.ap-northeast-1.aws.ce.redhat.com/pulp/repos//content/dist/rhel/rhui/server/7/7Server/x86_64/optional/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
Trying other mirror.

 One of the configured repositories failed (Red Hat Enterprise Linux Server 7 Optional (RPMs)),
 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. Disable the repository, 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 rhui-REGION-rhel-server-optional

     4. 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=rhui-REGION-rhel-server-optional.skip_if_unavailable=true

failure: repodata/repomd.xml from rhui-REGION-rhel-server-optional: [Errno 256] No more mirrors to try.
https://rhui2-cds01.ap-northeast-1.aws.ce.redhat.com/pulp/repos//content/dist/rhel/rhui/server/7/7Server/x86_64/optional/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
https://rhui2-cds02.ap-northeast-1.aws.ce.redhat.com/pulp/repos//content/dist/rhel/rhui/server/7/7Server/x86_64/optional/os/repodata/repomd.xml: [Errno 14] HTTPS Error 404 - Not Found
```



/etc/yum.repos.d/配下を確認すると、redhat-rhui.repo.rpmsaveが保存されています。

```bash
# ls /etc/yum.repos.d/
redhat-rhui-client-config.repo        rhui-load-balancers.conf
redhat-rhui.repo                redhat-rhui.repo.rpmsave
```


redhat-rhui.repo.rpmsaveをredhat-rhui.repoへ戻します。

```bash
# cp redhat-rhui.repo.rpmsave redhat-rhui.repo
```

もう1度yum updateする問題なく動きました。

```bash
# sudo yum update
Loaded plugins: amazon-id, rhui-lb
Resolving Dependencies
--> Running transaction check
---> Package dhclient.x86_64 12:4.2.5-27.el7 will be updated
---> Package dhclient.x86_64 12:4.2.5-27.el7_0.1 will be an update
---> Package dhcp-common.x86_64 12:4.2.5-27.el7 will be updated
---> Package dhcp-common.x86_64 12:4.2.5-27.el7_0.1 will be an update
---> Package dhcp-libs.x86_64 12:4.2.5-27.el7 will be updated
---> Package dhcp-libs.x86_64 12:4.2.5-27.el7_0.1 will be an update
---> Package openssl.x86_64 1:1.0.1e-34.el7_0.3 will be updated
---> Package openssl.x86_64 1:1.0.1e-34.el7_0.4 will be an update
---> Package openssl-libs.x86_64 1:1.0.1e-34.el7_0.3 will be updated
---> Package openssl-libs.x86_64 1:1.0.1e-34.el7_0.4 will be an update
--> Finished Dependency Resolution

Dependencies Resolved

========================================================================================
 Package        Arch     Version               Repository                          Size
========================================================================================
Updating:
 dhclient       x86_64   12:4.2.5-27.el7_0.1   rhui-REGION-rhel-server-releases   276 k
 dhcp-common    x86_64   12:4.2.5-27.el7_0.1   rhui-REGION-rhel-server-releases   169 k
 dhcp-libs      x86_64   12:4.2.5-27.el7_0.1   rhui-REGION-rhel-server-releases   126 k
 openssl        x86_64   1:1.0.1e-34.el7_0.4   rhui-REGION-rhel-server-releases   706 k
 openssl-libs   x86_64   1:1.0.1e-34.el7_0.4   rhui-REGION-rhel-server-releases   940 k

Transaction Summary
========================================================================================
Upgrade  5 Packages

Total download size: 2.2 M
```