由于依赖 /etc/redhat-release，在 EC2 上的 Amazon Linux 2 上为 postgres 9.6 rpm 安装 yum 失败
下面是日志
sudo yum install https://download.postgresql.org/pub/repos/yum/9.6/redhat/rhel-7-x86_64/pgdg-centos96-9.6-3.noarch.rpm
Loaded plugins: extras_suggestions, langpacks, priorities, update-motd
pgdg-centos96-9.6-3.noarch.rpm | 5.6 kB 00:00:00
Examining /var/tmp/yum-root-BrRLfO/pgdg-centos96-9.6-3.noarch.rpm: pgdg-redhat-repo-42.0-4.noarch
Marking /var/tmp/yum-root-BrRLfO/pgdg-centos96-9.6-3.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package pgdg-redhat-repo.noarch 0:42.0-4 will be installed
--> Processing Dependency: /etc/redhat-release for package: pgdg-redhat-repo-42.0-4.noarch amzn2-core | 2.4 kB 00:00:00
--> Processing Dependency: /etc/redhat-release for package: pgdg-redhat-repo-42.0-4.noarch
--> Finished Dependency Resolution
Error: Package: pgdg-redhat-repo-42.0-4.noarch (/pgdg-centos96-9.6-3.noarch)
Requires: /etc/redhat-release