cni-route-override examples

gistfile1.log

# Initial Config (without cni-route-override)
[tohayash@tohayash-lab ~]$ cat /etc/cni/net.d/87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@61c4fb920ba8 /]# ip route
default via 10.88.0.1 dev eth0 
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.33 
192.1.1.0/24 via 10.88.0.254 dev eth0 

# with cni-route-override (just added, nothing happen ;) 
[tohayash@tohayash-lab ~]$ cat 87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "route-overwrite"
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@6b5579af452f /]# ip route
default via 10.88.0.1 dev eth0 
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.34 
192.1.1.0/24 via 10.88.0.254 dev eth0 

# Flush all routes with cni-route-override
[tohayash@tohayash-lab ~]$ cat 87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "route-overwrite",
        "flushgateway": false,
        "flushroutes": true
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@272646f92216 /]# ip route
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.35 

Note: in case of flush all routes, we keep interface routes above.

# Flush gateway only
[tohayash@tohayash-lab ~]$ cat /etc/cni/net.d/87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "route-overwrite",
        "flushgateway": true,
        "flushroutes": false 
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@48d9f2e3d229 /]# ip route
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.37 
192.1.1.0/24 via 10.88.0.254 dev eth0 

# Add route
[tohayash@tohayash-lab ~]$ cat /etc/cni/net.d/87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "route-overwrite",
        "addroutes": [ {
            "dst": "192.168.0.0/24",
            "gw": "10.88.0.254"
        } ],
        "flushgateway": false,
        "flushroutes": false 
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@22969ab6ab24 /]# ip route
default via 10.88.0.1 dev eth0 
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.38 
192.1.1.0/24 via 10.88.0.254 dev eth0 
192.168.0.0/24 via 10.88.0.254 dev eth0 

# Delete route
[tohayash@tohayash-lab ~]$ cat /etc/cni/net.d/87-podman-bridge.conflist 
{
    "cniVersion": "0.3.1",
    "name": "podman",
    "plugins": [
      {
        "type": "bridge",
        "bridge": "cni0",
        "isGateway": true,
        "ipMasq": true,
        "ipam": {
            "type": "host-local",
            "subnet": "10.88.0.0/16",
            "routes": [
                { "dst": "0.0.0.0/0" }, 
                { "dst": "192.1.1.0/24", "gw": "10.88.0.254" }
            ]
        }
      },
      {
        "type": "route-overwrite",
        "delroutes": [ {
            "dst": "192.1.1.0/24"
        } ],
        "flushgateway": false,
        "flushroutes": false 
      },
      {
        "type": "portmap",
        "capabilities": {
          "portMappings": true
        }
      }
    ]
}
[tohayash@tohayash-lab ~]$ sudo podman run --network=podman -it docker.io/centos/tools:latest bash
[root@725f4724e0a7 /]# ip route
default via 10.88.0.1 dev eth0 
10.88.0.0/16 dev eth0 proto kernel scope link src 10.88.0.39