OCI: Yum Reports Error "Could not resolve host: yum$ociregion.$ocidomain; Unknown error"

Applies To:

Linux OS - Version Oracle Linux 6.0 and later

Oracle Cloud Infrastructure - Version N/A and later

Linux x86-64

Symptoms:

yum fails with the following error:

# yum -y install net-snmp
Loaded plugins: versionlock
Repository ol7_oci_included is listed more than once in the configuration
https://yum$ociregion.$ocidomain/repo/OracleLinux/OL7/MySQL80_community/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: yum$ociregion.$ocidomain; Unknown error"
Trying other mirror.

Cause:

When using a custom image, yum vars that normally reside in /etc/yum/vars/* may not exist. See below example:

# pwd
/etc/yum/vars
# ls -la
total 12
drwxr-xr-x. 2 root root 54 Jan 18 13:08 .
drwxr-xr-x. 8 root root 128 Jan 17 19:41 ..
-rw-r--r--. 1 root root 20 May 2 06:33 ocidomain
-rw-r--r--. 1 root root 14 May 2 06:33 ociregion
-rw-r--r--. 1 root root 13 May 2 06:33 region
# cat ocidomain
oci.oraclecloud.com
# cat ociregion
.us-ashburn-1
# cat region
us-ashburn-1
#