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adding tutorial to ROSA docs from mobb ninja site

This commit is contained in:
Alberto Diaz
2023-09-19 16:57:57 -04:00
committed by openshift-cherrypick-robot
parent e29c6224c5
commit 7dfefe74ba
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@@ -107,7 +107,9 @@ Topics:
- Name: Deploying the External DNS Operator on ROSA
File: cloud-experts-external-dns
- Name: Dynamically issuing certificates using the cert-manager Operator on ROSA
File: cloud-experts-dynamic-certificate-custom-domain
File: cloud-experts-dynamic-certificate-custom-domain
- Name: Assigning consistent egress IP for external traffic
File: cloud-experts-consistent-egress-ip
---
Name: Getting started
Dir: rosa_getting_started

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:_content-type: ASSEMBLY
[id="cloud-experts-consistent-egress-ip"]
= Tutorial: Assigning consistent egress IP for external traffic
include::_attributes/attributes-openshift-dedicated.adoc[]
:context: cloud-experts-consistent-egress-ip
toc::[]
// Mobb content metadata
// Brought into ROSA product docs 2023-09-19
// ---
// date: '2023-02-28'
// title: Assign Consistent Egress IP for External Traffic
// tags: ["OSD", "ROSA", "ARO"]
// authors:
// - 'Dustin Scott'
// ---
It might be desirable to assign a consistent IP address for traffic that leaves the cluster when configuring items such as security groups or other sorts of security controls which require an IP-based configuration. By default, {product-title} (ROSA) (using the OVN-Kubernetes CNI) assigns random IP addresses from a pool which makes configuring security lockdowns unpredictable or unnecessarily open. This guide shows you how to configure a set of predictable IP addresses for egress cluster traffic to meet common security standards and guidance and other potential use cases.
See the link:https://docs.openshift.com/container-platform/latest/networking/ovn_kubernetes_network_provider/configuring-egress-ips-ovn.html[OpenShift documentation on this topic] for more information.
== Prerequisites
* ROSA cluster deployed with OVN-Kubernetes
* OpenShift CLI (`oc`)
* ROSA CLI (`rosa`)
* `jq`
=== Environment
This sets environment variables for the tutorial so that you do not need to copy/paste in your own. Be sure to replace the `ROSA_MACHINE_POOL_NAME` variable if you wish to target a different Machine Pool.:
[source,terminal]
----
$ export ROSA_CLUSTER_NAME=$(oc get infrastructure cluster -o=jsonpath="{.status.infrastructureName}" | sed 's/-[a-z0-9]\{5\}$//')
$ export ROSA_MACHINE_POOL_NAME=Default
----
== Ensure capacity
For each public cloud provider, there is a limit on the number of IP addresses that may be assigned per node. This can affect the ability to assign an egress IP address. To verify sufficient capacity, you can run the following command to print out the currently assigned IP addresses versus the total capacity in order to identify any nodes which may affected:
[source,terminal]
----
$ oc get node -o json | \
jq '.items[] |
{
"name": .metadata.name,
"ips": (.status.addresses | map(select(.type == "InternalIP") | .address)),
"capacity": (.metadata.annotations."cloud.network.openshift.io/egress-ipconfig" | fromjson[] | .capacity.ipv4)
}'
----
.Example output
[source,terminal]
---
{
"name": "ip-10-10-145-88.ec2.internal",
"ips": [
"10.10.145.88"
],
"capacity": 14
}
{
"name": "ip-10-10-154-175.ec2.internal",
"ips": [
"10.10.154.175"
],
"capacity": 14
}
---
[NOTE]
====
The above example uses `jq` as a friendly filter. If you do not have `jq` installed, you can review the `metadata.annotations['cloud.network.openshift.io/egress-ipconfig']` field of each node manually to verify node capacity.
====
== Create the egress IP rule(s)
[NOTE]
====
Generally speaking, it would be ideal to label the nodes prior to assigning the egress IP addresses, however there is a bug that exists which needs to be fixed first. Once this is fixed, the process and documentation will be re-ordered to address this. See link:https://issues.redhat.com/browse/OCPBUGS-4969[OCPBUGS-4969].
====
=== Identify the egress IPs
Before creating the rules, we should identify which egress IPs that we will use. It should be noted that the egress IPs that you select should exist as a part of the subnets in which the worker nodes are provisioned into.
=== Reserve the egress IPs
It is recommended, but not required, to reserve the egress IPs that you have requested to avoid conflicts with the AWS VPC DHCP service. To do so, you can request explicit IP reservations by link:https://docs.aws.amazon.com/vpc/latest/userguide/subnet-cidr-reservation.html[following the AWS documentation for CIDR reservations].
== Deploy an egress IP to a namespace
Create a project to demonstrate assigning egress IP addresses based on a namespace selection:
[source,terminal]
----
$ oc new-project demo-egress-ns
----
Create the egress rule. This rule will ensure that egress traffic will be applied to all pods within the namespace that we just created using the `spec.namespaceSelector` field:
[source,terminal]
----
$ cat <<EOF | oc apply -f -
apiVersion: k8s.ovn.org/v1
kind: EgressIP
metadata:
name: demo-egress-ns
spec:
# NOTE: these egress IPs are within the subnet range(s) in which my worker nodes
# are deployed.
egressIPs:
- 10.10.100.253
- 10.10.150.253
- 10.10.200.253
namespaceSelector:
matchLabels:
kubernetes.io/metadata.name: demo-egress-ns
EOF
----
=== Assign an egress IP to a pod
Create a project to demonstrate assigning egress IP addresses based on a pod selection:
[source,terminal]
----
$ oc new-project demo-egress-pod
----
Create the egress rule. This rule will ensure that egress traffic will be applied to the pod which we just created using the `spec.podSelector` field. It should be noted that `spec.namespaceSelector` is a mandatory field:
[source,terminal]
----
$ cat <<EOF | oc apply -f -
apiVersion: k8s.ovn.org/v1
kind: EgressIP
metadata:
name: demo-egress-pod
spec:
# NOTE: these egress IPs are within the subnet range(s) in which my worker nodes
# are deployed.
egressIPs:
- 10.10.100.254
- 10.10.150.254
- 10.10.200.254
namespaceSelector:
matchLabels:
kubernetes.io/metadata.name: demo-egress-pod
podSelector:
matchLabels:
run: demo-egress-pod
EOF
----
=== Label the nodes
You can run `oc get egressips` and see that the egress IP assignments are pending.
.Example output
[source,terminal]
----
NAME EGRESSIPS ASSIGNED NODE ASSIGNED EGRESSIPS
demo-egress-ns 10.10.100.253
demo-egress-pod 10.10.100.254
----
To complete the egress IP assignment, we need to assign a specific label to the nodes. The egress IP rule that you created in a previous step only applies to nodes with the `k8s.ovn.org/egress-assignable` label. We want to ensure that label exists on only a specific machinepool as set using an environment variable in the set environment variables step.
Assign the necessary label to your machine pool using the following command:
[WARNING]
====
If you are reliant upon any node labels for your machinepool, this command will replace those labels. Be sure to input your desired labels into the `--labels` field to ensure your node labels persist.
====
[source,terminal]
----
$ rosa update machinepool ${ROSA_MACHINE_POOL_NAME} \
--cluster="${ROSA_CLUSTER_NAME}" \
--labels "k8s.ovn.org/egress-assignable="
----
=== Review the egress IPs
You can review the egress IP assignments by running `oc get egressips` which will produce output as follows:
.Example output
[source,terminal]
----
NAME EGRESSIPS ASSIGNED NODE ASSIGNED EGRESSIPS
demo-egress-ns 10.10.100.253 ip-10-10-156-122.ec2.internal 10.10.150.253
demo-egress-pod 10.10.100.254 ip-10-10-156-122.ec2.internal 10.10.150.254
----
== Test the egress IP rule
=== Deploy a sample application
To test the rule, we will create a service which is locked down only to the egress IP addresses in which we have specified. This will simulate an external service which is expecting a small subset of IP addresses.
Run the echoserver which gives us some helpful information:
[source,terminal]
----
$ oc -n default run demo-service --image=gcr.io/google_containers/echoserver:1.4
----
Expose the pod as a service, limiting the ingress (via the `.spec.loadBalancerSourceRanges` field) to the service to only the egress IP addresses in which we specified our pods should be using:
[source,terminal]
----
$ cat <<EOF | oc apply -f -
apiVersion: v1
kind: Service
metadata:
name: demo-service
namespace: default
annotations:
service.beta.kubernetes.io/aws-load-balancer-scheme: "internal"
service.beta.kubernetes.io/aws-load-balancer-internal: "true"
spec:
selector:
run: demo-service
ports:
- port: 80
targetPort: 8080
type: LoadBalancer
externalTrafficPolicy: Local
# NOTE: this limits the source IPs that are allowed to connect to our service. It
# is being used as part of this demo, restricting connectivity to our egress
# IP addresses only.
# NOTE: these egress IPs are within the subnet range(s) in which my worker nodes
# are deployed.
loadBalancerSourceRanges:
- 10.10.100.254/32
- 10.10.150.254/32
- 10.10.200.254/32
- 10.10.100.253/32
- 10.10.150.253/32
- 10.10.200.253/32
EOF
----
Retrieve the load balancer hostname as the `LOAD_BALANCER_HOSTNAME` environment variable which you can copy and use for following steps:
[source,terminal]
----
$ export LOAD_BALANCER_HOSTNAME=$(oc get svc -n default demo-service -o json | jq -r '.status.loadBalancer.ingress[].hostname')
----
=== Test namespace egress
Test the namespace egress rule which was created previously. The following starts an interactive shell which allows you to run curl against the demo service:
[source,terminal]
----
$ oc run \
demo-egress-ns \
-it \
--namespace=demo-egress-ns \
--env=LOAD_BALANCER_HOSTNAME=$LOAD_BALANCER_HOSTNAME \
--image=registry.access.redhat.com/ubi9/ubi -- \
bash
----
Once inside the pod, you can send a request to the load balancer, ensuring that you can successfully connect:
[source,terminal]
----
$ curl -s http://$LOAD_BALANCER_HOSTNAME
----
You should see output similar to the following, indicating a successful connection. It should be noted that the `client_address` below is the internal IP address of the load balancer rather than our egress IP. Successful connectivity (by limiting the service to `.spec.loadBalancerSourceRanges`) is what provides a successful demonstration:
.Example output
[source,terminal]
----
CLIENT VALUES:
client_address=10.10.207.247
command=GET
real path=/
query=nil
request_version=1.1
request_uri=http://internal-a3e61de18bfca4a53a94a208752b7263-148284314.us-east-1.elb.amazonaws.com:8080/
SERVER VALUES:
server_version=nginx: 1.10.0 - lua: 10001
HEADERS RECEIVED:
accept=*/*
host=internal-a3e61de18bfca4a53a94a208752b7263-148284314.us-east-1.elb.amazonaws.com
user-agent=curl/7.76.1
BODY:
-no body in request-
----
You can safely exit the pod once you are done:
[source,terminal]
----
$ exit
----
=== Test pod egress
Test the pod egress rule which was created previously. The following starts an interactive shell which allows you to run curl against the demo service:
[source,terminal]
----
$ oc run \
demo-egress-pod \
-it \
--namespace=demo-egress-pod \
--env=LOAD_BALANCER_HOSTNAME=$LOAD_BALANCER_HOSTNAME \
--image=registry.access.redhat.com/ubi9/ubi -- \
bash
----
Once inside the pod, you can send a request to the load balancer, ensuring that you can successfully connect:
[source,terminal]
----
$ curl -s http://$LOAD_BALANCER_HOSTNAME
----
You should see output similar to the following, indicating a successful connection. It should be noted that the `client_address` below is the internal IP address of the load balancer rather than our egress IP. Successful connectivity (by limiting the service to `.spec.loadBalancerSourceRanges`) is what provides a successful demonstration:
.Example output
[source,terminal]
----
CLIENT VALUES:
client_address=10.10.207.247
command=GET
real path=/
query=nil
request_version=1.1
request_uri=http://internal-a3e61de18bfca4a53a94a208752b7263-148284314.us-east-1.elb.amazonaws.com:8080/
SERVER VALUES:
server_version=nginx: 1.10.0 - lua: 10001
HEADERS RECEIVED:
accept=*/*
host=internal-a3e61de18bfca4a53a94a208752b7263-148284314.us-east-1.elb.amazonaws.com
user-agent=curl/7.76.1
BODY:
-no body in request-
----
You can safely exit the pod once you are done:
[source,terminal]
----
$ exit
----
=== Test blocked egress
Alternatively to a successful connection, you can see that the traffic is successfully blocked when the egress rules do not apply. Unsuccessful connectivity (by limiting the service to `.spec.loadBalancerSourceRanges`) is what provides a successful demonstration in this scenario:
[source,terminal]
----
$ oc run \
demo-egress-pod-fail \
-it \
--namespace=demo-egress-pod \
--env=LOAD_BALANCER_HOSTNAME=$LOAD_BALANCER_HOSTNAME \
--image=registry.access.redhat.com/ubi9/ubi -- \
bash
----
Once inside the pod, you can send a request to the load balancer:
[source,terminal]
----
$ curl -s http://$LOAD_BALANCER_HOSTNAME
----
The above command should hang. You can safely exit the pod once you are done:
[source,terminal]
----
$ exit
----
== Clean up
You can cleanup your cluster by running the following commands:
[source,terminal]
----
$ oc delete svc demo-service -n default; \
$ oc delete pod demo-service -n default; \
$ oc delete project demo-egress-ns; \
$ oc delete project demo-egress-pod; \
$ oc delete egressip demo-egress-ns; \
$ oc delete egressip demo-egress-pod
----
You can cleanup the assigned node labels by running the following commands:
[WARNING]
====
If you are reliant upon any node labels for your machinepool, this command will replace those labels. Be sure to input your desired labels into the `--labels` field to ensure your node labels persist.
====
[source,terminal]
----
$ rosa update machinepool ${ROSA_MACHINE_POOL_NAME} \
--cluster="${ROSA_CLUSTER_NAME}" \
--labels ""
----