ori-edge / k8s_gateway

A CoreDNS plugin to resolve all types of external Kubernetes resources
Apache License 2.0
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k8s-gateway breaks ability of internal systems to resolve external domain names #150

Closed airtonix closed 2 years ago

airtonix commented 2 years ago

when deploying the following, all future attempts to resolve any other dns queries fails.

---
apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease

metadata:
  name: excoredns
  namespace: kube-system

spec:
    interval: 5m
    install:
        createNamespace: true

    chart:
        spec:
            chart: k8s-gateway
            version: 1.1.9
            interval: 5m
            sourceRef:
                kind: HelmRepository
                name: k8s-gateway-helm-repo
                namespace: flux-system

    values:
      domain: kube.lan
      watchedResources: [ 'Ingress' ]
      fallthrough:
        enabled: true

if i add the following :

      extraZonePlugins: |
        forward . 1.1.1.1 1.0.0.1 {
          tls_servername cloudflare-dns.com
        }

Then dns queries for external hostnames are able to leave my local network and get resolved, but then so does every other query for the cluster.

networkop commented 2 years ago

So far everything you've described seems to be working as expected. What exactly is the issue you're seeing?

airtonix commented 2 years ago

let me start again:

this: https://github.com/airtonix/clusterfiles/blob/master/manifests/infrastructure/base/dns/release.yaml#L1-L37

fails to apply.because:

if i manually make sure the docker image for k8s_gateway is on the node before applying the helm chart, then things work. but then i have other problems.

After applying the above:


I want my cluster to not require a dns server outside my lan to resolve entries in the cluster.

I have:

What I want:

What I'm doing:

The order of fluxcd kustomizations:

I setup the single node cluster like so:

  1. if it's not clean, ssh in and run sudo k3s-uninstall.sh, because i want all this to work without any hand holding.

  2. install k3s on the node: with clusterfiles master <hostname> <sshuser> <sshkey>

    $ clusterfiles master kube zenobius ~/.ssh/id_ed25519
    # ... lots of successful log output spam here... much postive, very expected. everyone happy.
  3. bootstrap fluxcd on the master node (which triggers it to apply ☝🏻 the above sequence of kustomizations) with GITHUB_TOKEN=supersecret clusterfiles bootstrap <clustername> <githubowner> <githubrepo>

    $ GITHUB_TOKEN=ghp_trolololololol clusterfiles bootstrap default airtonix clusterfiles
    # ... lots of successful log output spam here... much postive, very expected. everyone happy. 
  4. Now fire up a status report watching the deployment:

    
    $ watch -n 1 "clusterfiles status"

... usually prints out


![image](https://user-images.githubusercontent.com/61225/191668004-cc18d7af-83fd-4898-b400-2f1a95d219a1.png)

I can also fire up Lens, and watch the events of the "cluster", and this is where I usually watch the following occur: 

- new commit is seen on the git repo
- it applies the sources, registeres all the helm repos etc
- tries to start applying the infrastructure group, but something fails around the k8s-gateway: 
  - either something fails with applying the k8s-gateway helm chart
  - or it succeeds and further image pulls fail.
networkop commented 2 years ago

as it applies, something interfers with the ability of the cluster to pull docker images. the error looks like it can't resolve dns queries any more.

This means your k8s/k3s node DNS resolver is misconfigured.

dns queries to the outside world fail to resolve for anything. so now the rest of the fluxcd process throws errors everywhere because it can't pull other docker images.

Seems like a symptom of the same problem.

Just so that we're clear, our plugin, k8s_gateway, is designed to resolve external k8s resources (ingress, services etc.). You can combine it with other plugins, like forward if you also want it to act as a DNS forwarder, but this is entirely optional. For all intra-cluster DNS needs, you have to use standard kubernetes DNS add-on (coredns with kubernetes plugin).

Here are some of my thoughts based on what I understood from your description:

i only want dns queries for .kube.lan to be handled by 192.168.8.222 i do not want any non .kube.lan dns queries from the rest of my lan to be sent to 192.168.8.222

This should be the responsibility of dnsmasq/openwrt resolver.

i do not want dns queries for any internal cluster domain names to be leaving the cluster. i want queries for *.kube.lan that originate within the cluster to instead resolve to internal cluster ip addresses, and not 192.168.8.222

Both are the responsibility of standard kubernetes DNS add-on.

i want queries for the rest of the universe to continue to leave the cluster

You need to use the forward plugin for that.

airtonix commented 2 years ago

yep ok, i get what you say k8s-gateway is doing and it makes sense that all k8s-gateway should be doing is fielding requests from outside the cluster.

sidenote: I'm currently running another host on my network that uses just docker-compose and a single traefik instance. Queries are handled by an adguard instance that rewrites requests for *.home.lan to the ip address of that docker-compose/traefik host. I want to decomission this host for a fluxcd setup so volumes are backedup offsite and the host itself can be treated like cattle.

So here's me re-provisioning the host again:

clusterfiles on git master on aws (ap-southeast-2) took 10s 
x clusterfiles master jadakren zenobius ~/.ssh/id_ed25519
Running: k3sup install
2022/09/22 18:58:47 jadakren
Public IP: jadakren
[INFO]  Finding release for channel stable
[INFO]  Using v1.24.4+k3s1 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.24.4+k3s1/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.24.4+k3s1/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
Rancher K3s Common (stable)                     5.3 kB/s | 2.9 kB     00:00    
Dependencies resolved.
================================================================================
 Package         Arch       Version         Repository                     Size
================================================================================
Installing:
 k3s-selinux     noarch     1.2-2.el8       rancher-k3s-common-stable      20 k

Transaction Summary
================================================================================
Install  1 Package

Total download size: 20 k
Installed size: 94 k
Downloading Packages:
k3s-selinux-1.2-2.el8.noarch.rpm                 28 kB/s |  20 kB     00:00    
--------------------------------------------------------------------------------
Total                                            27 kB/s |  20 kB     00:00     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Running scriptlet: k3s-selinux-1.2-2.el8.noarch                           1/1 
  Installing       : k3s-selinux-1.2-2.el8.noarch                           1/1 
  Running scriptlet: k3s-selinux-1.2-2.el8.noarch                           1/1 
  Verifying        : k3s-selinux-1.2-2.el8.noarch                           1/1 

Installed:
  k3s-selinux-1.2-2.el8.noarch                                                  

Complete!
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Skipping /usr/local/bin/ctr symlink to k3s, command exists in PATH at /usr/bin/ctr
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service β†’ /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s
Result: [INFO]  Finding release for channel stable
[INFO]  Using v1.24.4+k3s1 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.24.4+k3s1/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.24.4+k3s1/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
Rancher K3s Common (stable)                     5.3 kB/s | 2.9 kB     00:00    
Dependencies resolved.
================================================================================
 Package         Arch       Version         Repository                     Size
================================================================================
Installing:
 k3s-selinux     noarch     1.2-2.el8       rancher-k3s-common-stable      20 k

Transaction Summary
================================================================================
Install  1 Package

Total download size: 20 k
Installed size: 94 k
Downloading Packages:
k3s-selinux-1.2-2.el8.noarch.rpm                 28 kB/s |  20 kB     00:00    
--------------------------------------------------------------------------------
Total                                            27 kB/s |  20 kB     00:00     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                        1/1 
  Running scriptlet: k3s-selinux-1.2-2.el8.noarch                           1/1 
  Installing       : k3s-selinux-1.2-2.el8.noarch                           1/1 
  Running scriptlet: k3s-selinux-1.2-2.el8.noarch                           1/1 
  Verifying        : k3s-selinux-1.2-2.el8.noarch                           1/1 

Installed:
  k3s-selinux-1.2-2.el8.noarch                                                  

Complete!
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Skipping /usr/local/bin/ctr symlink to k3s, command exists in PATH at /usr/bin/ctr
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
[INFO]  systemd: Starting k3s
 Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service β†’ /etc/systemd/system/k3s.service.

Saving file to: /home/zenobius/Projects/Mine/Github/clusterfiles/kubeconfig

# Test your cluster with:
export KUBECONFIG=/home/zenobius/Projects/Mine/Github/clusterfiles/kubeconfig
kubectl config set-context default
kubectl get node -o wide

🐳 k3sup needs your support: https://github.com/sponsors/alexellis
✚ generating manifests
βœ” manifests build completed
β–Ί installing components in flux-system namespace
CustomResourceDefinition/buckets.source.toolkit.fluxcd.io created
CustomResourceDefinition/gitrepositories.source.toolkit.fluxcd.io created
CustomResourceDefinition/helmcharts.source.toolkit.fluxcd.io created
CustomResourceDefinition/helmreleases.helm.toolkit.fluxcd.io created
CustomResourceDefinition/helmrepositories.source.toolkit.fluxcd.io created
CustomResourceDefinition/ocirepositories.source.toolkit.fluxcd.io created
Namespace/flux-system created
ServiceAccount/flux-system/helm-controller created
ServiceAccount/flux-system/source-controller created
ClusterRole/crd-controller-flux-system created
ClusterRoleBinding/cluster-reconciler-flux-system created
ClusterRoleBinding/crd-controller-flux-system created
Service/flux-system/source-controller created
Deployment/flux-system/helm-controller created
Deployment/flux-system/source-controller created
β—Ž verifying installation
βœ” helm-controller: deployment ready
βœ” source-controller: deployment ready
βœ” install finished

Everything here is standard k3s, I haven't modified anything.

If I run a oneshot docker container that does a google.com ping:

$ kubectl run dnsutils-ping-google --restart=Never --rm -i --tty --image registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3 -- ping google.com            

If you don't see a command prompt, try pressing enter.
64 bytes from mel05s01-in-f14.1e100.net (142.250.70.206): icmp_seq=2 ttl=54 time=28.0 ms
64 bytes from mel05s01-in-f14.1e100.net (142.250.70.206): icmp_seq=3 ttl=54 time=28.6 ms
64 bytes from mel05s01-in-f14.1e100.net (142.250.70.206): icmp_seq=4 ttl=54 time=28.2 ms
64 bytes from mel05s01-in-f14.1e100.net (142.250.70.206): icmp_seq=5 ttl=54 time=36.6 ms
64 bytes from mel05s01-in-f14.1e100.net (142.250.70.206): icmp_seq=6 ttl=54 time=28.8 ms
^C
--- google.com ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5006ms
rtt min/avg/max/mdev = 28.013/30.528/36.619/3.156 ms
pod "dnsutils-ping-google" deleted

Not sure if this matters, but also try to ping internal address:

$ kubectl run dnsutils-ping-google --restart=Never --rm -i --tty --image registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3 -- ping kubernetes.default

If you don't see a command prompt, try pressing enter.
From 100.80.0.1 icmp_seq=2 Packet filtered
From 100.80.0.1 icmp_seq=3 Packet filtered
From 100.80.0.1 icmp_seq=4 Packet filtered
From 100.80.0.1 icmp_seq=5 Packet filtered
From 100.80.0.1 icmp_seq=6 Packet filtered
^C
--- kubernetes.default.svc.cluster.local ping statistics ---
6 packets transmitted, 0 received, +6 errors, 100% packet loss, time 5006ms

pod "dnsutils-ping-google" deleted
pod default/dnsutils-ping-google terminated (Error)

The dns is up?

x kubectl get pods --namespace=kube-system -l k8s-app=kube-dns

NAME                      READY   STATUS    RESTARTS   AGE
coredns-b96499967-8mfkb   1/1     Running   0          6m29s

But looks like the logfile is spammed with warnings... not sure how to get the start of that log file:

 kubectl logs --namespace=kube-system -l k8s-app=kube-dns

[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server
[WARNING] No files matching import glob pattern: /etc/coredns/custom/*.server

rest of the kube-system

> kubectl get svc --namespace=kube-system

NAME             TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)                      AGE
kube-dns         ClusterIP      10.43.0.10     <none>          53/UDP,53/TCP,9153/TCP       7m3s
metrics-server   ClusterIP      10.43.242.36   <none>          443/TCP                      7m2s
traefik          LoadBalancer   10.43.160.77   192.168.8.222   80:31456/TCP,443:30222/TCP   6m5s

The dns is running on these interfaces and ports

$ kubectl get endpoints kube-dns --namespace=kube-system

NAME       ENDPOINTS                                  AGE
kube-dns   10.42.0.6:53,10.42.0.6:53,10.42.0.6:9153   6m58s

This is the core-dns configmap:


  GNU nano 6.0                                                    /tmp/kubectl-edit-2969051488.yaml                                                              
# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
data:
  Corefile: |
    .:53 {
    errors
    health
    ready
    kubernetes cluster.local in-addr.arpa ip6.arpa {
          pods insecure
          fallthrough in-addr.arpa ip6.arpa
        }
    hosts /etc/coredns/NodeHosts {
          ttl 60
          reload 15s
          fallthrough
        }
    prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
    reload
    loadbalance
    }
    import /etc/coredns/custom/*.server
  NodeHosts: |
    192.168.8.222 jadakren
kind: ConfigMap
metadata:
  annotations:
    objectset.rio.cattle.io/applied: H4sIAAAAAAAA/4yQwWrzMBCEX0Xs2fEf20nsX9BDybH02lMva2kdq1Z2g6SkBJN3L8IUCiVtbyNGOzvfzoAn90IhOmHQcKmgAIsJQc+wl0CD8wQaSr1t1PzKSil>
    objectset.rio.cattle.io/id: ""
    objectset.rio.cattle.io/owner-gvk: k3s.cattle.io/v1, Kind=Addon
    objectset.rio.cattle.io/owner-name: coredns
    objectset.rio.cattle.io/owner-namespace: kube-system
  creationTimestamp: "2022-09-22T09:29:17Z"
  labels:
    objectset.rio.cattle.io/hash: bce283298811743a0386ab510f2f67ef74240c57
  name: coredns
  namespace: kube-system
  resourceVersion: "370"
  uid: bab78907-7b4f-4a19-9f48-ffafd0efb1f0

But now when i apply the k8s-gateway:

clusterfiles on git master [!] on aws (ap-southeast-2) 
> helm repo add k8s_gateway https://ori-edge.github.io/k8s_gateway/

"k8s_gateway" has been added to your repositories

clusterfiles on git master [!] on aws (ap-southeast-2) 
> helm install exdns --set domain=kube.lan k8s_gateway/k8s-gateway

NAME: exdns
LAST DEPLOYED: Thu Sep 22 19:15:21 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None

clusterfiles on git master [!] on aws (ap-southeast-2) 
> kubectl get events --sort-by='.lastTimestamp'          

LAST SEEN   TYPE      REASON                    OBJECT                                    MESSAGE
15m         Normal    Scheduled                 pod/dnsutils-ping-google                  Successfully assigned default/dnsutils-ping-google to jadakren
21m         Normal    Starting                  node/jadakren                             
14m         Normal    Scheduled                 pod/dnsutils-ping-google                  Successfully assigned default/dnsutils-ping-google to jadakren
16m         Normal    Scheduled                 pod/dnsutils-ping-google                  Successfully assigned default/dnsutils-ping-google to jadakren
5m10s       Normal    Scheduled                 pod/exdns-k8s-gateway-68f497c4d8-tgm45    Successfully assigned default/exdns-k8s-gateway-68f497c4d8-tgm45 to jadakren
21m         Warning   InvalidDiskCapacity       node/jadakren                             invalid capacity 0 on image filesystem
21m         Normal    NodeHasSufficientMemory   node/jadakren                             Node jadakren status is now: NodeHasSufficientMemory
21m         Normal    NodeHasNoDiskPressure     node/jadakren                             Node jadakren status is now: NodeHasNoDiskPressure
21m         Normal    NodeHasSufficientPID      node/jadakren                             Node jadakren status is now: NodeHasSufficientPID
21m         Normal    NodeAllocatableEnforced   node/jadakren                             Updated Node Allocatable limit across pods
21m         Normal    Starting                  node/jadakren                             Starting kubelet.
21m         Normal    Synced                    node/jadakren                             Node synced successfully
21m         Normal    NodeReady                 node/jadakren                             Node jadakren status is now: NodeReady
21m         Normal    RegisteredNode            node/jadakren                             Node jadakren event: Registered Node jadakren in Controller
16m         Normal    Pulling                   pod/dnsutils-ping-google                  Pulling image "registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3"
15m         Normal    Created                   pod/dnsutils-ping-google                  Created container dnsutils-ping-google
15m         Normal    Started                   pod/dnsutils-ping-google                  Started container dnsutils-ping-google
15m         Normal    Pulled                    pod/dnsutils-ping-google                  Successfully pulled image "registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3" in 24.546335601s
15m         Normal    Started                   pod/dnsutils-ping-google                  Started container dnsutils-ping-google
15m         Normal    Created                   pod/dnsutils-ping-google                  Created container dnsutils-ping-google
15m         Normal    Pulled                    pod/dnsutils-ping-google                  Container image "registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3" already present on machine
14m         Normal    Pulled                    pod/dnsutils-ping-google                  Container image "registry.k8s.io/e2e-test-images/jessie-dnsutils:1.3" already present on machine
14m         Normal    Created                   pod/dnsutils-ping-google                  Created container dnsutils-ping-google
14m         Normal    Started                   pod/dnsutils-ping-google                  Started container dnsutils-ping-google
5m11s       Normal    ScalingReplicaSet         deployment/exdns-k8s-gateway              Scaled up replica set exdns-k8s-gateway-68f497c4d8 to 1
5m11s       Normal    SuccessfulCreate          replicaset/exdns-k8s-gateway-68f497c4d8   Created pod: exdns-k8s-gateway-68f497c4d8-tgm45
5m10s       Normal    UpdatedIngressIP          service/exdns-k8s-gateway                 LoadBalancer Ingress IP addresses updated: 192.168.8.222
5m5s        Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Failed to pull image "quay.io/oriedge/k8s_gateway:v0.3.2": rpc error: code = Unknown desc = failed to pull and unpack image "quay.io/oriedge/k8s_gateway:v0.3.2": failed to resolve reference "quay.io/oriedge/k8s_gateway:v0.3.2": failed to do request: Head "https://quay.io/v2/oriedge/k8s_gateway/manifests/v0.3.2": dial tcp: lookup quay.io on 127.0.0.53:53: read udp 127.0.0.1:46480->127.0.0.53:53: read: connection refused
5m5s        Normal    AppliedDaemonSet          service/exdns-k8s-gateway                 Applied LoadBalancer DaemonSet kube-system/svclb-exdns-k8s-gateway-08adea51
4m35s       Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Failed to pull image "quay.io/oriedge/k8s_gateway:v0.3.2": rpc error: code = Unknown desc = failed to pull and unpack image "quay.io/oriedge/k8s_gateway:v0.3.2": failed to resolve reference "quay.io/oriedge/k8s_gateway:v0.3.2": failed to do request: Head "https://quay.io/v2/oriedge/k8s_gateway/manifests/v0.3.2": dial tcp: lookup quay.io on 127.0.0.53:53: read udp 127.0.0.1:54085->127.0.0.53:53: i/o timeout
3m51s       Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Failed to pull image "quay.io/oriedge/k8s_gateway:v0.3.2": rpc error: code = Unknown desc = failed to pull and unpack image "quay.io/oriedge/k8s_gateway:v0.3.2": failed to resolve reference "quay.io/oriedge/k8s_gateway:v0.3.2": failed to do request: Head "https://quay.io/v2/oriedge/k8s_gateway/manifests/v0.3.2": dial tcp: lookup quay.io on 127.0.0.53:53: read udp 127.0.0.1:36634->127.0.0.53:53: read: no route to host
3m4s        Normal    Pulling                   pod/exdns-k8s-gateway-68f497c4d8-tgm45    Pulling image "quay.io/oriedge/k8s_gateway:v0.3.2"
2m43s       Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Failed to pull image "quay.io/oriedge/k8s_gateway:v0.3.2": rpc error: code = Unknown desc = failed to pull and unpack image "quay.io/oriedge/k8s_gateway:v0.3.2": failed to resolve reference "quay.io/oriedge/k8s_gateway:v0.3.2": failed to do request: Head "https://quay.io/v2/oriedge/k8s_gateway/manifests/v0.3.2": dial tcp: lookup quay.io on 127.0.0.53:53: read udp 127.0.0.1:58308->127.0.0.53:53: i/o timeout
2m43s       Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Error: ErrImagePull
2m29s       Warning   Failed                    pod/exdns-k8s-gateway-68f497c4d8-tgm45    Error: ImagePullBackOff
2m15s       Normal    BackOff                   pod/exdns-k8s-gateway-68f497c4d8-tgm45    Back-off pulling image "quay.io/oriedge/k8s_gateway:v0.3.2"
  1. I'm pretty sure my openwrt dnsmasq dns forwarding is good. nothing untoward going on there.
  2. I'm not confident that I know what the proper configuration i should have in my kube-dns ?
airtonix commented 2 years ago

so yeah in summary:

airtonix commented 2 years ago

i also just tried manually pulling and runnin the image, ( no dramas ) :

clusterfiles on git master [!] on aws (ap-southeast-2) took 5s 
> kubectl run k8s-gateway-pull-test --restart=Never --rm -i --tty --image quay.io/oriedge/k8s_gateway:v0.3.2                                                                                                                  
If you don't see a command prompt, try pressing enter.

^C[INFO] SIGINT: Shutting down
pod "k8s-gateway-pull-test" deleted
airtonix commented 2 years ago

πŸ˜… i might have been running an old version of your helm chart this whole time...

just updated to 1.1.15 and also removed the createNamespace part...

but it still throws an error about failing to pull the image.

image

if however i prewarm the image cache before trying to apply the helm chart it works.

   clusterfiles on git master [!] on aws (ap-southeast-2) 
x kubectl run k8s-gateway-pull-test --restart=Never --rm -i --tty --image quay.io/oriedge/k8s_gateway:v0.3.2  
pod "k8s-gateway-pull-test" deleted
error: timed out waiting for the condition

once the helm chart is in deployment, nothing i do will allow me to resolve external dns queries

networkop commented 2 years ago

hm.. this is really strange. I can't imagine how k8s-gateway might interfere with node's ability to pull images. and that's even before it pulls its own image! interesting. Let's start with some obvious things:

airtonix commented 2 years ago
  • What happens if you uninstall the helm chart? Do you have DNS connectivity after that?
clusterfiles on git master [!] on aws (ap-southeast-2) 
❯ ssh jadakren -C "nslookup google.com"
;; connection timed out; no servers could be reached

clusterfiles on git master [+] on aws (ap-southeast-2) 
❯ flux delete kustomization infrastructure
# time passes

clusterfiles on git master [+] on aws (ap-southeast-2) 
❯ ssh jadakren -C "nslookup google.com"
Server:     127.0.0.53
Address:    127.0.0.53#53

Non-authoritative answer:
Name:   google.com
Address: 142.250.71.78
Name:   google.com
Address: 2404:6800:4015:802::200e
  • Can you show the contents of the /etc/resolv.conf from the k3s node? does it point at the openwrt router?

Since the node is at this point just a Fedora Linux 35 (Workstation Edition):

❯ cat /etc/resolv.conf

... snip lots of commented blah blah

nameserver 127.0.0.53
options edns0 trust-ad
search lan

also since :

❯ cat /run/systemd/resolve/resolv.conf
# This is /run/systemd/resolve/resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 192.168.8.10
search lan

192.168.8.10 is the ip address of a third machine in my lan that holds my current docker-compose-ansible-thing. An adguard-home instance is exposed there on port :53

So something i read about k8s and core-dns etc, is that on linux it will use the nodes /etc/resolv.conf ?

Does it literally symlink mount it writable into the cluster?

  • What happens if you remove the domain delegation from openwrt? remove any references to the IP of the k3s node and see if the queries are resolved again.
  1. removed the dns forwarding: image
  2. waited for fluxcd scheduled sync to occur and see that it needs to reapply the removal i did above. ☝🏻
  3. same errors are back:

image

  • Can you manually apply the helm-generated manifests one by one and see at which point it breaks? i.e. do helm template, split the result into multiple files and just kubectl apply -f them one by one. I wonder if any of them overwrite something that doesn't belong to us?

completely emptied the "infrastructure" kustomization:

---
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
  []
  # - ../base/cert-manager
  # - ../base/dns
  # - ../base/cache
  # - ../base/storages

waited for it to sync and remove.

clusterfiles on git master [>] on aws (ap-southeast-2) 
> flux resume kustomization infrastructure
β–Ί resuming kustomization infrastructure in flux-system namespace
βœ” kustomization resumed
β—Ž waiting for Kustomization reconciliation
βœ” Kustomization reconciliation completed
βœ” applied revision master/344484cd226a77fe632b1d8ed731e8178fb48bbe

clusterfiles on git master on aws (ap-southeast-2) took 3m 
> ssh jadakren -C "nslookup google.com"    
Server:     127.0.0.53
Address:    127.0.0.53#53

Non-authoritative answer:
Name:   google.com
Address: 142.250.71.78
Name:   google.com
Address: 2404:6800:4015:802::200e

prepare the indiviual bits:

clusterfiles/charts on git master on aws (ap-southeast-2) 
x  helm template k8s-gateway https://ori-edge.github.io/k8s_gateway/charts/k8s-gateway-1.1.15.tgz --set domain=kube.lan --output-dir .

wrote ./k8s-gateway/templates/serviceaccount.yaml
wrote ./k8s-gateway/templates/configmap.yaml
wrote ./k8s-gateway/templates/rbac.yaml
wrote ./k8s-gateway/templates/rbac.yaml
wrote ./k8s-gateway/templates/service.yaml
wrote ./k8s-gateway/templates/deployment.yaml

suspend flux

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> flux suspend kustomization infrastructure --all
β–Ί suspending kustomization infrastructure in flux-system namespace
βœ” kustomization suspended

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> flux suspend kustomization sources --all        
β–Ί suspending kustomization sources in flux-system namespace
βœ” kustomization suspended

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> flux suspend kustomization apps --all   
βœ— no Kustomization objects found in flux-system namespace

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> flux suspend kustomization flux-system --all
β–Ί suspending kustomization flux-system in flux-system namespace
βœ” kustomization suspended

now lets apply the bits individually:

serviceaccount

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> kubectl apply -f ./k8s-gateway/templates/serviceaccount.yaml                                                                        
serviceaccount/k8s-gateway created

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> ssh jadakren -C "nslookup google.com"                       
Server:     127.0.0.53
Address:    127.0.0.53#53

Non-authoritative answer:
Name:   google.com
Address: 142.250.70.206
Name:   google.com
Address: 2404:6800:4006:812::200e

configmap


clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
x kubectl apply -f ./k8s-gateway/templates/configmap.yaml     
configmap/k8s-gateway created

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> ssh jadakren -C "nslookup google.com"                  
Server:     127.0.0.53
Address:    127.0.0.53#53

Non-authoritative answer:
Name:   google.com
Address: 142.250.67.14
Name:   google.com
Address: 2404:6800:4006:811::200e

rbac

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> kubectl apply -f ./k8s-gateway/templates/rbac.yaml     
clusterrole.rbac.authorization.k8s.io/k8s-gateway created
clusterrolebinding.rbac.authorization.k8s.io/k8s-gateway created

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> ssh jadakren -C "nslookup google.com"             
Server:     127.0.0.53
Address:    127.0.0.53#53

Non-authoritative answer:
Name:   google.com
Address: 142.250.67.14
Name:   google.com
Address: 2404:6800:4015:802::200e

service

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> kubectl apply -f ./k8s-gateway/templates/service.yaml 
service/k8s-gateway created

clusterfiles/charts on git master [?] on aws (ap-southeast-2) 
> ssh jadakren -C "nslookup google.com"                
;; connection timed out; no servers could be reached

deployment

clusterfiles/charts on git master [?] on aws (ap-southeast-2) took 15s 
x kubectl apply -f ./k8s-gateway/templates/deployment.yaml 
deployment.apps/k8s-gateway created

clusterfiles/charts on git master on aws (ap-southeast-2) took 4s 
x ssh jadakren -C "nslookup google.com"
;; connection timed out; no servers could be reached

And sure enough, back in my event log:

image

airtonix commented 2 years ago

Here's the generated templates I used above: https://github.com/airtonix/clusterfiles/commit/128126c70bd0011746ac0aaef9ad23f7a3c453ae

airtonix commented 2 years ago

additionally, the situation for resolvd on the node:

clusterfiles/charts on git master on aws (ap-southeast-2) 
x ssh jadakren -C "cat /etc/resolv.conf"                  
# This is /run/systemd/resolve/stub-resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients to the
# internal DNS stub resolver of systemd-resolved. This file lists all
# configured search domains.
#
# Run "resolvectl status" to see details about the uplink DNS servers
# currently in use.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 127.0.0.53
options edns0 trust-ad
search lan

clusterfiles/charts on git master on aws (ap-southeast-2) 
> ssh jadakren -C "cat  /run/systemd/resolve/resolv.conf"
# This is /run/systemd/resolve/resolv.conf managed by man:systemd-resolved(8).
# Do not edit.
#
# This file might be symlinked as /etc/resolv.conf. If you're looking at
# /etc/resolv.conf and seeing this text, you have followed the symlink.
#
# This is a dynamic resolv.conf file for connecting local clients directly to
# all known uplink DNS servers. This file lists all configured search domains.
#
# Third party programs should typically not access this file directly, but only
# through the symlink at /etc/resolv.conf. To manage man:resolv.conf(5) in a
# different way, replace this symlink by a static file or a different symlink.
#
# See man:systemd-resolved.service(8) for details about the supported modes of
# operation for /etc/resolv.conf.

nameserver 192.168.8.10
search lan

clusterfiles/charts on git master on aws (ap-southeast-2) 
> ssh jadakren -C "resolvctl status"                 
zsh:1: command not found: resolvctl

clusterfiles/charts on git master on aws (ap-southeast-2) 
x ssh jadakren -C "resolvectl status"
Global
       Protocols: LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub

Link 2 (enp0s31f6)
    Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
         Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.8.10
       DNS Servers: 192.168.8.10
        DNS Domain: lan

Link 3 (virbr0)
Current Scopes: none
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 4 (docker0)
Current Scopes: none
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 541 (flannel.1)
Current Scopes: LLMNR/IPv4 LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 542 (cni0)
Current Scopes: LLMNR/IPv4 LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 544 (veth80e4867d)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 546 (vethd93c4ed4)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 549 (vethbdf5a636)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 550 (vethff150521)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 551 (veth27a38309)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 552 (veth6bc3aab6)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 553 (veth873354ce)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 554 (vethe4bd35d6)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 555 (veth17d83c8b)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 560 (veth51585a2b)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported

Link 561 (veth22d6d541)
Current Scopes: LLMNR/IPv6
     Protocols: -DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
airtonix commented 2 years ago

if i explicitly tell it to use my adguard-home dns server:


clusterfiles/charts on git master on aws (ap-southeast-2) 
x ssh jadakren -C "host google.com 192.168.8.10" 
Using domain server:
Name: 192.168.8.10
Address: 192.168.8.10#53
Aliases: 

google.com has address 142.250.70.206
google.com has IPv6 address 2404:6800:4006:812::200e
google.com mail is handled by 10 smtp.google.com.
airtonix commented 2 years ago

you can probs replicate this by doing the following:

I suspect a hacky way is to have some kind of ordering in the helm file that runs the deployment before the service.

A probably better long term fix is understanding why the nodes ability to resolve dns queries is affected by the service? (turn of systemd-resolveconf?)

networkop commented 2 years ago

oh ok, now I think I know what's happening. So your node is running systemd-resolved which is listening on 127.0.0.53:53. When you install k8s-gateway helm chart, it creates a LoadBalancer-type service that's listening on port 53. This, in turn, creates an iptables rules to redirect all traffic for port 53 to that service's backends (which don't exist yet). This also explains that external DNS resolution doesn't work until you add the forward plugin to the k8s_gateway, since all external DNS lookups go to 127.0.0.53 and end up redirected to the k8s_gateway pod.

I think the simplest workaround would be to change your /etc/resolv.conf to point to 192.168.8.10 directly, instead of going via systemd-resolved. Do you wanna try that?

airtonix commented 2 years ago

i'll give it a go tomorrow morning. πŸ‘πŸ»

Thanks heaps for your paitence and experience here ❀️

airtonix commented 2 years ago

looks like this guy experienced exactly my problem: http://asynchrono.us/disabling-systemd-resolved-on-fedora-coreos-33.html

airtonix commented 2 years ago

πŸ‘πŸ» If i disable systemd-resolved and wipe k3s then restart, it all works.

I imagine this isn't usually a problem for people running docker via DockerForWin, or DockerForMac or some cloud-init based linux os that doesn't setup resolveconf.

#mysterysolved

rgstephens commented 2 years ago

Thanks for this thread. I also ran into this issue on Ubuntu with k3s. To summarize, on each node in my cluster I did the following:

The deployed the helm chart (which enables the forward plugin by default).