Major changes

• Update kubernetes version to 1.21.6 (#8142, @oomichi)
• Add a new option metrics_server_resizer (default to false) to control the addon-resizer container deployment in metrics-server pod (#8018, @oomichi)
• Add an optional fallback to node drain during cluster upgrades using --disable-eviction flag (#8102, @utkuozdemir)
• Ensure apparmor is installed on Ubuntu (#8036, @rtsp)
• Default DNS replica count is now set to the minimum value between 2 and the length of k8s_cluster inventory group (#8109, @smasset)

Applications

• [Openstack] Fix a bug where Openstack cloud provider could not be used with username/password (#8021, @bl0m1)

Network

• [Calico] Check if 'plugins' key exists in calico_cni_config object allowing user to add nodes using both playbooks (#7717, @dlouks)
• [Calico] Fix typha prometheus causing a deployment error (#8005, @ericlake)
• [Calico] Increase node probe timeouts and add calico_node_readinessprobe_timeout/calico_node_livenessprobe_timeout to tune them (#7981, @cristicalin)
• [Cilium] Fix operator metrics activation (enable-metrics key missing) (#8000, @L3o-pold)

Bug or Regression

• Add missing proxy settings for subscription-manager in RHEL OS (if http_proxy is defined) (#8012, @oomichi)
• Fix CentOS7 issue with allowPrivilegeEscalation value from metrics-server (#8014, @oomichi)
• Fix k8s-certs-renew cp path wrongly using /usr/bin/ (#7992, @lazybetrayer)
• Fix containerd failed to start if apparmor is not installed (#8011, @rtsp)

Other note worthy changes

• Use kube_config_dir for kubeconfig instead of hard path in multiple plays (#7996, @oomichi)