Default Networks don't have default routes

[electrocucaracha]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

bug feature

What happened: The default route is not adding the default network into the routing table

$ kubectl exec -ti test -- ip route
10.244.0.0/16 via 10.244.1.1 dev eth0 
10.244.1.0/24 dev eth0 scope link  src 10.244.1.5

What you expected to happen:

$ kubectl exec -ti test -- ip route
default via 10.244.1.1 dev eth0
10.244.0.0/16 via 10.244.1.1 dev eth0 
10.244.1.0/24 dev eth0 scope link  src 10.244.1.5

How to reproduce it: I've defined a Default Cluster Network using Flannel as CNI

cat <<EOF | kubectl apply -f -
apiVersion: danm.k8s.io/v1
kind: ClusterNetwork
metadata:
  name: default
spec:
  NetworkID: flannel
  NetworkType: flannel
EOF

Once DANM setup is completed, I've created a single Pod with no explicit connection.

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod 
metadata:
  name: test
spec:
  containers:
    - name: test
      image: alpine:3.11
      command: ["sleep"]
      args: ["infinity"]
EOF

Anything else we need to know?: This issue affects pods that are trying to connect to services outside of the Pod subnet(10.244.0.0/16), e. g. Kubernetes Services(10.96.0.0/12).

Environment:

• DANM version (use danm -version): v4.2.0
• Kubernetes version (use kubectl version): v1.18.2
• DANM configuration (K8s manifests, kubeconfig files, CNI config file):

  {
  "cniVersion": "0.3.1",
  "name": "danm-cni-network",
  "type": "danm",
  "kubeconfig": "/etc/cni/net.d/danm.d/kubeconfig"
  }

• OS (e.g. from /etc/os-release): NAME="Ubuntu" VERSION="18.04.5 LTS (Bionic Beaver)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 18.04.5 LTS" VERSION_ID="18.04" HOME_URL="https://www.ubuntu.com/" SUPPORT_URL="https://help.ubuntu.com/" BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/" PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy" VERSION_CODENAME=bionic UBUNTU_CODENAME=bionic
• Kernel (e.g. uname -a): Linux ubuntu1804.localdomain 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

[Levovar]

default route not being added is usually the sign of your Flannel config being wrong. please share

also please read https://github.com/nokia/danm/issues/135

[electrocucaracha]

This was the flannel configuration file:

{
  "name": "cbr0",
  "cniVersion": "0.3.1",
  "plugins": [
    {   
      "type": "flannel",
      "delegate": {
        "hairpinMode": true,
        "isDefaultGateway": true
      }   
    },  
    {   
      "type": "portmap",
      "capabilities": {
        "portMappings": true
      }   
    }   
  ]
}

So I changed to this one

{
  "name": "cbr0",
  "type": "flannel",
  "cniVersion": "0.3.1",
  "delegate": {
    "hairpinMode": true,
    "isDefaultGateway": true
  }
}

And the default routes are added

kubectl exec -ti test -- ip route
default via 10.244.1.1 dev eth0 
10.244.0.0/16 via 10.244.1.1 dev eth0 
10.244.1.0/24 dev eth0 scope link  src 10.244.1.9 

Thanks for the quick response on this.