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Added example about targeting deployments through the use of selectors (targeting labels)

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savagebidoof 2023-04-27 03:26:32 +02:00
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7
Istio/06-AuthorizationPolicy/03-target-deployments/01-namespace.yaml Executable file
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apiVersion: v1
kind: Namespace
metadata:
name: foo
labels:
istio-injection: "enabled"
---

382
Istio/06-AuthorizationPolicy/03-target-deployments/README.md Executable file
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---
gitea: none
include_toc: true
---
# Continues from
- [01-target-namespaces](../01-target-namespaces)
> **Note:**\
> On this example there is minimal changes to the configuration to involve targeting the deployment resources through label filtering.
## Description
Bla bla bla
In this example we will be targeting the labels set to the deployments, while keeping part of the previous AuthorizationPolicy configuration to maintain its behavior.
[//]: # (For such, it's important to check the labels set in the Istio ingress that we will be using.)
[//]: # ()
[//]: # (On my case, in the gateway I will be targeting/using the Istio ingress `ingressgateway`.)
[//]: # ()
[//]: # (I would **strongly** recommend checking yours through the following command, as to proceed we should be aware of which are our possible labels options.)
[//]: # ()
[//]: # (```shell)
[//]: # (kubectl get deployments -A -l istio=ingressgateway -o jsonpath='{.items[].spec.template.metadata.labels}'| jq)
[//]: # (```)
[//]: # (```json)
[//]: # ({)
[//]: # ( "app": "istio-ingressgateway",)
[//]: # ( "chart": "gateways",)
[//]: # ( "heritage": "Tiller",)
[//]: # ( "install.operator.istio.io/owning-resource": "unknown",)
[//]: # ( "istio": "ingressgateway",)
[//]: # ( "istio.io/rev": "default",)
[//]: # ( "operator.istio.io/component": "IngressGateways",)
[//]: # ( "release": "istio",)
[//]: # ( "service.istio.io/canonical-name": "istio-ingressgateway",)
[//]: # ( "service.istio.io/canonical-revision": "latest",)
[//]: # ( "sidecar.istio.io/inject": "false")
[//]: # (})
[//]: # (```)
[//]: # ()
[//]: # (Based on the list displayed, I would suggest focusing on the following options:)
[//]: # ()
[//]: # (```json)
[//]: # ({)
[//]: # ("istio": "ingressgateway",)
[//]: # ("operator.istio.io/component": "IngressGateways",)
[//]: # ("app": "istio-ingressgateway",)
[//]: # (})
[//]: # (```)
[//]: # ()
[//]: # (The label `"service.istio.io/canonical-revision": "latest"` could be reasonable to use, in very specific situations, as depending on the implementation/environment or procedures that we might use in the future, it's something to keep in mind in case of being configured.)
[//]: # ()
[//]: # ()
# Configuration
## AuthorizationPolicy
### Allow nothing (deny all not matched)
#### default namespace
If the action is not specified, it will deploy the rule as "ALLOW".
Here we are deploying a rule that allows the traffic that it matches, yet as it has no conditions, it will never match.
```yaml
# Deny all requests to namespace default
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: allow-nothing
namespace: default
```
Citing the [Authorization Policy documentation from Istio](https://istio.io/latest/docs/reference/config/security/authorization-policy), regarding the evaluation behavior of these rules:
1. If there are any CUSTOM policies that match the request, evaluate and deny the request if the evaluation result is deny.
2. If there are any DENY policies that match the request, deny the request.
3. If there are no ALLOW policies for the workload, allow the request.
4. If any of the ALLOW policies match the request, allow the request.
5. Deny the request.
On this scenario, as we don't have any DENY or CUSTOM rule, we skip right into the 3rd scenario.
This rule is being applied to the workload (due being a rule that affects the whole namespace), and for such the 3rd scenario is not being applied either.
On the 4rth, scenario, as the rule deployed, even if it's on ALLOW mode, has no conditions, it won't allow the traffic either.
And finally, as any of the above scenarios allowed the traffic of the request, it ends getting denied.
For such, the creation of this "empty" rule, has set the authorization mode on the not explicitly allowed request to "DENY ALL".
#### foo namespace
Same behavior as above, this time applied to the namespace `foo`
```yaml
# Deny all requests to namespace foo
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: allow-nothing
namespace: foo
spec:
{}
```
## ALLOW
#### byeworld-allow-from-istio-system
As we have a service deployed, and the traffic will come through the Istio Load Balancer (at least on my environment). I have set a rule that will allow all the traffic coming from a resource located in the namespace `istio-system`.
This rule will be applied to the deployments that have set the following label `app: byeworld`, and deployed in the namespace `istio-system`.
> **Note:**\
> As this rule will be deployed in the root namespace `istio-system` (it's my root namespace in **MY** environment, review your Istio configuration to ensure which is **YOUR** root namespace).\
> By deploying the rule in the root namespace, it gets applied to all namespaces, I have set this to ensure that there are minor differences on the configuration in comparison on which example this is based on. As well this will allow us to confirm tha the labels are being applied correctly.
```yaml
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: byeworld-allow-from-istio-system
namespace: istio-system
spec:
selector:
matchLabels:
app: byeworld
action: ALLOW
rules:
- from:
- source:
namespaces: ["istio-system"]
```
#### byeworld-allow-head-from-default
I have set a new rule, that will allow the traffic coming from the namespace `default`, as long the method used is `HEAD` and is not targeting the path `/secret`.
This rule will be applied to the deployments that have set the following label `app: byeworld`, and deployed in the namespace `istio-system`.
> **Note:**\
> This will be deployed in the root namespace `istio-system` (it's my root namespace in **MY** environment, review your Istio configuration to ensure which is **YOUR** root namespace).\
> By deploying the rule in the root namespace, it gets applied to all namespaces, I have set this to ensure that there are minor differences on the configuration in comparison on which example this is based on. As well this will allow us to confirm tha the labels are being applied correctly.
```yaml
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: byeworld-allow-head-from-default
namespace: istio-system
spec:
action: ALLOW
selector:
matchLabels:
app: byeworld
rules:
- from:
- source:
namespaces: ["default"]
to:
- operation:
methods: ["HEAD"]
notPaths: ["/secret*"]
```
# Walkthrough
## Deploy the resources
```shell
kubectl apply -f ./
```
```text
namespace/foo created
authorizationpolicy.security.istio.io/allow-nothing created
authorizationpolicy.security.istio.io/byeworld-allow-from-istio-system created
authorizationpolicy.security.istio.io/byeworld-allow-head-from-default created
service/helloworld created
deployment.apps/helloworld-nginx created
service/byeworld created
deployment.apps/byeworld-nginx created
gateway.networking.istio.io/helloworld-gateway created
virtualservice.networking.istio.io/helloworld-vs create
```
## Test resources
### Curl / LB requests / requests from external traffic
#### Get LB IP
```shell
kubectl get svc istio-ingressgateway -n istio-system
```
```text
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
istio-ingressgateway LoadBalancer 10.97.47.216 192.168.1.50 15021:31316/TCP,80:32012/TCP,443:32486/TCP 39h
```
#### helloworld
Due to the rule `allow-nothing` created on the namespace `istio-system`, which is being applied to all the namespaces, we are not hitting any rule that explicitly allows us, and for such, the traffic is being denied.
For such we receive the status code `403` (**Forbidden**)
```shell
curl 192.168.1.50/helloworld -I
```
```text
HTTP/1.1 403 Forbidden
content-length: 19
content-type: text/plain
date: Thu, 27 Apr 2023 01:20:06 GMT
server: istio-envoy
x-envoy-upstream-service-time: 108
```
#### byeworld
As we created the rule `byeworld-allow-from-istio-system` created in the namespace `foo`, which allows all the traffic coming from a resource located in the namespace `istio-system`, and the load balancer used is located in the namespace `istio-system`, the traffic is allowed.
For such we receive the code `200`.
```shell
curl 192.168.1.50/byeworld --head
```
```text
HTTP/1.1 200 OK
server: istio-envoy
date: Thu, 27 Apr 2023 01:20:49 GMT
content-type: text/html
content-length: 615
last-modified: Tue, 28 Mar 2023 15:01:54 GMT
etag: "64230162-267"
accept-ranges: bytes
x-envoy-upstream-service-time: 104
```
### Connectivity between the deployments
> **NOTE:**\
> The command `curl`, when uses the flag `--head` or `-I`, the request sent will be a `HEAD` request.
>
> It's important to be aware of that due the rule configured, where one of the targets was the method used, specifically targeted the method `HEAD`.
>
> On this example, all request will be done with the method `HEAD` unless specified otherwise.
#### helloworld towards byeworld
It works.
Due to the rule `byeworld-allow-head-from-default` deployed on the namespace `foo`, which allowed the traffic coming from the namespace `default` as long it used the method `HEAD` and wasn't targeting the path `/secret`, the request is allowed.
```shell
kubectl exec -i -t "$(kubectl get pod -l app=helloworld | tail -n 1 | awk '{print $1}')" -- curl http://byeworld.foo.svc.cluster.local:9090 --head
```
```text
HTTP/1.1 200 OK
server: envoy
date: Thu, 27 Apr 2023 01:20:58 GMT
content-type: text/html
content-length: 615
last-modified: Tue, 28 Mar 2023 15:01:54 GMT
etag: "64230162-267"
accept-ranges: bytes
x-envoy-upstream-service-time: 86
```
#### helloworld towards byeworld (GET REQUEST)
This example is made on base on the last comand executed, where the request sent uses the `HEAD` method.
On this example the flag `--head` is removed, which causes the command `curl` to send a request of method `GET`.
As the rule created required the method to be `HEAD`, it causes the request to not be allowed, and finally as there are no rules that allow this request, it results in failure.
```shell
kubectl exec -i -t "$(kubectl get pod -l app=helloworld | tail -n 1 | awk '{print $1}')" -- curl http://byeworld.foo.svc.cluster.local:9090
```
```text
RBAC: access denied%
```
#### byeworld towards helloworld
It fails.
As expected, like when accessing through the Load Balancer, we receive the status code `403` (**Forbidden**).
The `HEAD` request is irrelevant on this scenario, yet using it as I like this output more.
```shell
kubectl exec -i -n foo -t "$(kubectl get pod -n foo -l app=byeworld | tail -n 1 | awk '{print $1}')" -- curl http://helloworld.default.svc.cluster.local:8080 --head
```
```text
HTTP/1.1 403 Forbidden
content-length: 19
content-type: text/plain
date: Thu, 27 Apr 2023 01:21:10 GMT
server: envoy
x-envoy-upstream-service-time: 96
```
#### helloworld towards byeworld/secret
Due to the configuration set on the rule `byeworld-allow-head-from-default`, one of the conditions for it to allow the traffic, was to not access the path/match the prefix expression `/secret*`.
This causes the traffic to not be allowed.
```shell
kubectl exec -i -t "$(kubectl get pod -l app=helloworld | tail -n 1 | awk '{print $1}')" -- curl http://byeworld.foo.svc.cluster.local:9090/secret --head
```
```text
HTTP/1.1 403 Forbidden
content-length: 19
content-type: text/plain
date: Thu, 27 Apr 2023 01:21:18 GMT
server: envoy
x-envoy-upstream-service-time: 3
```
#### helloworld towards byeworld/not-found
On this example, we can notice how even if the request was allowed due meeting all the requirements, it still results in the error code `404` (Not Found).
This 404 error is raised by the destination service, yet before being able to handle such request, firstly the traffic required to be allowed, meaning that even if we target as a destination path a non-existent resource, we will need to match the requirements for the traffic to be allowed.
```shell
kubectl exec -i -t "$(kubectl get pod -l app=helloworld | tail -n 1 | awk '{print $1}')" -- curl http://byeworld.foo.svc.cluster.local:9090/not-found --head
```
```text
HTTP/1.1 404 Not Found
server: envoy
date: Thu, 27 Apr 2023 01:21:31 GMT
content-type: text/html
content-length: 153
x-envoy-upstream-service-time: 56
```
# Links of interest
- https://istio.io/latest/docs/reference/config/security/authorization-policy/

22
Istio/06-AuthorizationPolicy/04-audit/authentication.yaml → Istio/06-AuthorizationPolicy/03-target-deployments/authentication.yaml
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@ -1,11 +1,3 @@
# Deny all requests to namespace foo
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: allow-nothing
namespace: foo
spec:
{}
---
# Deny all requests to namespace default
apiVersion: security.istio.io/v1beta1
@ -19,9 +11,12 @@ spec:
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: allow-from-istio-system
namespace: foo
name: byeworld-allow-from-istio-system
namespace: istio-system
spec:
selector:
matchLabels:
app: byeworld
action: ALLOW
rules:
- from:
@ -31,10 +26,13 @@ spec:
apiVersion: security.istio.io/v1beta1
kind: AuthorizationPolicy
metadata:
name: allow-head-from-default
namespace: foo
name: byeworld-allow-head-from-default
namespace: istio-system
spec:
action: ALLOW
selector:
matchLabels:
app: byeworld
rules:
- from:
- source:

14
Istio/06-AuthorizationPolicy/04-audit/deployment.yaml → Istio/06-AuthorizationPolicy/03-target-deployments/deployment.yaml
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@ -1,4 +1,3 @@
# https://github.com/istio/istio/blob/master/samples/helloworld/helloworld.yaml
apiVersion: v1
kind: Service
metadata:
@ -8,18 +7,12 @@ metadata:
service: helloworld
spec:
ports:
- port: 80
- port: 8080
name: http
targetPort: 80
selector:
app: helloworld
---
#apiVersion: v1
#kind: ServiceAccount
#metadata:
# name: istio-helloworld
# labels:
# account:
---
apiVersion: apps/v1
kind: Deployment
metadata:
@ -36,13 +29,12 @@ spec:
labels:
app: helloworld
spec:
# serviceAccountName: istio-helloworld
containers:
- name: helloworld
image: nginx
resources:
requests:
cpu: "100m"
imagePullPolicy: IfNotPresent #Always
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80

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Istio/06-AuthorizationPolicy/04-audit/gateway.yaml → Istio/06-AuthorizationPolicy/03-target-deployments/gateway.yaml
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@ -28,8 +28,18 @@ spec:
exact: /helloworld
route:
- destination:
host: helloworld
host: helloworld.default.svc.cluster.local
port:
number: 80
number: 8080
rewrite:
uri: "/"
- match:
- uri:
exact: /byeworld
route:
- destination:
host: byeworld.foo.svc.cluster.local
port:
number: 9090
rewrite:
uri: "/"