Bug 1836018 - AWS UPI: Both Internal and External load balancers for kube-apiserver should use /readyz
Summary: AWS UPI: Both Internal and External load balancers for kube-apiserver should ...
Alias: None
Product: OpenShift Container Platform
Classification: Red Hat
Component: Installer
Version: 4.5
Hardware: Unspecified
OS: Unspecified
Target Milestone: ---
: 4.6.0
Assignee: Russell Teague
QA Contact: Yunfei Jiang
Depends On:
Blocks: 1873280 1876581
TreeView+ depends on / blocked
Reported: 2020-05-14 23:46 UTC by W. Trevor King
Modified: 2020-11-09 15:10 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Cause: Healthcheck probes not defined on AWS UPI deployed load balancers Consequence: Load balancers do not properly detect when an API endpoint is no longer available and may still direct traffic causing client failures. Fix: Added Healthcheck probes to AWS UPI deployed load balancers Result: Load balancers properly detect when API endpoints are not available and do not route traffic to offline nodes.
Clone Of: 1828382
Last Closed: 2020-10-27 15:59:49 UTC
Target Upstream Version:

Attachments (Terms of Use)
install log (73.81 KB, text/plain)
2020-06-11 10:37 UTC, Yunfei Jiang
no flags Details

System ID Private Priority Status Summary Last Updated
Github openshift installer pull 3709 0 None closed Bug 1836018: upi/aws/cloudformation: Define healthcheck probes for LBs 2020-11-13 01:53:58 UTC
Github openshift installer pull 3757 0 None closed Bug 1836018: Use /healthz for mco 2020-11-13 01:53:58 UTC
Red Hat Product Errata RHBA-2020:4196 0 None None None 2020-10-27 15:59:53 UTC

Description W. Trevor King 2020-05-14 23:46:53 UTC
+++ This bug was initially created as a clone of Bug #1828382 +++

Description of problem:
Load balancers (both internal and external) for kube-apiserver should use /readyz for back-end health check.

After scanning the github repo, we found the following platforms do not use /readyz for backend health check.



Please investigate the following, not sure if it needs to be addressed 

The above health checks use default TCP rule which breaks graceful termination. When the apiserver receives a KILL signal /readyz will start reporting failure. This gives the load balancer a chance to detect an instance that is rolling out and take appropriate action.    

We should use AWS lb rules as a reference for consistency - https://github.com/openshift/installer/blob/master/data/data/aws/vpc/master-elb.tf#L87

"health_check {
    healthy_threshold   = 2
    unhealthy_threshold = 2
    interval            = 10
    port                = 6443
    protocol            = "HTTPS"
    path                = "/readyz"

Version-Release number of the following components:
OpenShift 4.5. 

How reproducible:

Steps to Reproduce:
1. Run an upgrade job on the specified infrastructure. 

You will see that the load balancer is sending request to an apiserver while it's down. 

Actual results:
An example: https://prow.svc.ci.openshift.org/view/gcs/origin-ci-test/logs/release-openshift-ocp-installer-e2e-azure-serial-4.4/1542

Apr 26 21:45:14.063: INFO: Unexpected error listing nodes: Get https://api.ci-op-hvqc8pgw-0ba00.ci.azure.devcluster.openshift.com:6443/api/v1/nodes?fieldSelector=spec.unschedulable%3Dfalse&resourceVersion=0: dial tcp connect: connection refused

Expected results:
The load balancer should identify the kube-apiserer instance that is being rolled out in time and forward requests to another instance that is serving. Ideally, we should not see any "dial tcp connect: connection refused" error while kube-apiserver is being rolled out.

Bug 1828382 handled installer-provisioned Azure.  This clone is for the user-provisioned AWS recommendations.  Dropping severity down to medium, because user-provisioned recommendations are suggesting approaches, not telling the user what they should be doing without thinking.

Comment 1 Abhinav Dahiya 2020-05-18 17:25:26 UTC
Won't be able to get to it this sprint.

Comment 6 Yunfei Jiang 2020-06-11 10:37:40 UTC
Created attachment 1696713 [details]
install log

Comment 9 Yunfei Jiang 2020-06-17 03:24:32 UTC
verified on 4.6.0-0.nightly-2020-06-16-214732. FAILED.
Same problem as described in comment #5 https://bugzilla.redhat.com/show_bug.cgi?id=1836018#c5

Comment 10 Abhinav Dahiya 2020-06-18 23:48:51 UTC
can you provide must-gather
and info on the AWS target groups like the backends, health probe info etc.

Comment 11 Russell Teague 2020-06-19 15:57:48 UTC
After several attempts to resolve this issue, a adequate fix has not yet been identified.  Flagging with UpcomingSprint for review.

Comment 13 Yunfei Jiang 2020-06-22 10:36:15 UTC
Hello Abhinav,

following is the target group info, and log-bundle is attached.
vpc-id is vpc-00bb6a475a9898cd2, let me know if you need further information.

1. checking health check settings:

aws elbv2 describe-target-groups --names yunji-Inter-F33KVHQZNMLM

    "TargetGroups": [
            "TargetGroupArn": "arn:aws:elasticloadbalancing:us-east-2:301721915996:targetgroup/yunji-Inter-F33KVHQZNMLM/0a5d717106179edd",
            "TargetGroupName": "yunji-Inter-F33KVHQZNMLM",
            "Protocol": "TCP",
            "Port": 22623,
            "VpcId": "vpc-00bb6a475a9898cd2",
            "HealthCheckProtocol": "HTTPS",
            "HealthCheckPort": "22623",
            "HealthCheckEnabled": true,
            "HealthCheckIntervalSeconds": 10,
            "HealthCheckTimeoutSeconds": 10,
            "HealthyThresholdCount": 2,
            "UnhealthyThresholdCount": 2,
            "HealthCheckPath": "/readyz",
            "Matcher": {
                "HttpCode": "200-399"
            "LoadBalancerArns": [
            "TargetType": "ip"

2. checking healthy status:

aws elbv2 describe-target-health --target-group-arn arn:aws:elasticloadbalancing:us-east-2:301721915996:targetgroup/yunji-Inter-F33KVHQZNMLM/0a5d717106179edd | jq .TargetHealthDescriptions[].TargetHealth.State

Comment 14 Abhinav Dahiya 2020-06-24 15:07:36 UTC
> https://github.com/openshift/installer/pull/3757/files#diff-c60d83f04b0b1233e1739f06c356299fR221

We changed the health endpoint, but it looks like you are still using the old CF template.

> aws elbv2 describe-target-groups --names yunji-Inter-F33KVHQZNMLM
> {
>     "TargetGroups": [
>         {
>             "TargetGroupArn":
> "arn:aws:elasticloadbalancing:us-east-2:301721915996:targetgroup/yunji-Inter-
> F33KVHQZNMLM/0a5d717106179edd",
>             "TargetGroupName": "yunji-Inter-F33KVHQZNMLM",
>             "Protocol": "TCP",
>             "Port": 22623,
>             "VpcId": "vpc-00bb6a475a9898cd2",
>             "HealthCheckProtocol": "HTTPS",
>             "HealthCheckPort": "22623",
>             "HealthCheckEnabled": true,
>             "HealthCheckIntervalSeconds": 10,
>             "HealthCheckTimeoutSeconds": 10,
>             "HealthyThresholdCount": 2,
>             "UnhealthyThresholdCount": 2,
>             "HealthCheckPath": "/readyz",
>             "Matcher": {
>                 "HttpCode": "200-399"
>             },
>             "LoadBalancerArns": [
> "arn:aws:elasticloadbalancing:us-east-2:301721915996:loadbalancer/net/
> yunjiang-22bz0185-c4wkt-int/bd15404005f6e841"
>             ],
>             "TargetType": "ip"
>         }
>     ]
> }

Please use the latest CF template and try again.

Comment 15 Yunfei Jiang 2020-06-29 08:48:31 UTC
verified on registry.svc.ci.openshift.org/ocp/release:4.6.0-0.ci-2020-06-28-020831. PASS.

Comment 17 errata-xmlrpc 2020-10-27 15:59:49 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (OpenShift Container Platform 4.6 GA Images), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


Note You need to log in before you can comment on or make changes to this bug.