[Packaging] Drop CentOS 7 RPM package

[jiasli]

Description
Close #22726

According to https://wiki.centos.org/About/Product, CentOS 7 has already reached its maintenance phase since 2020-08-06:

CentOS 7 still only has Python 3.6, but Python 3.6 has been deprecated on 2021-12-23 (https://www.python.org/downloads/).

We are already releasing el8 package for RHEL 8 and CentOS Stream 8 which uses Python 3.9 (#21655, #22606).

Azure Python SDK tried to remove Python 3.6 support last year (Azure/azure-sdk-for-python#20691), but added Python 3.6 back later (Azure/azure-sdk-for-python#22459) as a grace period.

Email: Deprecation of Python 3.6 in SDK

Python SDK officially declared dropping Python 3.6 support on 2022-07-02 in

• Drop 3.6 in main Readme azure-sdk-for-python#25047

Python SDK's main README now shows:

https://github.com/Azure/azure-sdk-for-python#prerequisites

Changes

• Drop BuildRpmPackageCentOS7 from build pipeline
• Let TestRpmPackage use the el8 package built by Red Hat UBI 8

Tests for 3.6 is dropped by #20865.

[jiasli]

Should we drop https://github.com/Azure/azure-cli/blob/22bd24508d36982a7f88c0ce307b2b4c6f0ebdcc/scripts/release/rpm/centos7.dockerfile as well? Customer can still use this file to build their own RPMs for CentOS 7, but at their own risk.

[bebound]

Test Rpm Package fails because test_rpm_package.py is hard coded as python3.6 but ubi8 use python3.9

[jiasli]

yum is deprecated. We use the latest dnf. Note localinstall is now a deprecated alias of install: https://dnf.readthedocs.io/en/latest/command_ref.html#install-command

[bebound]

The bash's intent is incorrect (it should be 2 whitespace), could you please fix this in this PR?

[jiasli]

You mean "indent"? You do have sharp eyes. 😀 There are some other occurrences:

azure-cli/azure-pipelines.yml

Lines 500 to 526 in e7279d8

	- bash: |
	#!/bin/bash
	root=$(cd $(dirname $0); pwd)
	set -evx
	CLI_VERSION=`cat $BUILD_ARTIFACTSTAGINGDIRECTORY/metadata/version`
	HOMEBREW_UPSTREAM_URL=`curl -Ls -o /dev/null -w %{url_effective} https://api.github.com/repos/Azure/azure-cli/tarball/$BUILD_SOURCEVERSION`
	docker_files=$(cd $BUILD_SOURCESDIRECTORY/scripts/release/homebrew/docker; pwd)
	src_files=$(cd $BUILD_SOURCESDIRECTORY/src; pwd)
	echo "Generating formula in docker container ... "
	docker run -v $docker_files:/mnt/scripts \
	-v $src_files:/mnt/src \
	-e CLI_VERSION=$CLI_VERSION \
	-e HOMEBREW_UPSTREAM_URL=$HOMEBREW_UPSTREAM_URL \
	--name azurecli \
	python:3.10 \
	/mnt/scripts/run.sh
	# clean up
	rm -rf $BUILD_ARTIFACTSTAGINGDIRECTORY/metadata
	docker cp azurecli:azure-cli.rb $BUILD_ARTIFACTSTAGINGDIRECTORY/azure-cli.rb
	docker rm --force azurecli

Actually YAML does support arbitrary number of spaces as indent. Let's do this in another PR.

[jiasli]

Good news! BuildRpmPackageUbi8 is not as slow as before. Now it only takes ~20min.