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Merge pull request #30134 from ixodie/patch-10

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Removing GCE bridging/routing config tweaks
This commit is contained in:
Kubernetes Prow Robot
2021-12-05 12:06:32 -08:00
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parent 04d4d3e86b 7d9051266d
commit ec41959cc1
1 changed files with 0 additions and 43 deletions
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content/en/docs/concepts/cluster-administration/networking.md
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@@ -169,49 +169,6 @@ With this toolset DANM is able to provide multiple separated network interfaces,
network that satisfies the Kubernetes requirements. Many network that satisfies the Kubernetes requirements. Many
people have reported success with Flannel and Kubernetes. people have reported success with Flannel and Kubernetes.
### Google Compute Engine (GCE)
For the Google Compute Engine cluster configuration scripts, [advanced
routing](https://cloud.google.com/vpc/docs/routes) is used to
assign each VM a subnet (default is `/24` - 254 IPs). Any traffic bound for that
subnet will be routed directly to the VM by the GCE network fabric. This is in
addition to the "main" IP address assigned to the VM, which is NAT'ed for
outbound internet access. A linux bridge (called `cbr0`) is configured to exist
on that subnet, and is passed to docker's `--bridge` flag.
Docker is started with:
```shell
DOCKER_OPTS="--bridge=cbr0 --iptables=false --ip-masq=false"
```
This bridge is created by Kubelet (controlled by the `--network-plugin=kubenet`
flag) according to the `Node`'s `.spec.podCIDR`.
Docker will now allocate IPs from the `cbr-cidr` block. Containers can reach
each other and `Nodes` over the `cbr0` bridge. Those IPs are all routable
within the GCE project network.
GCE itself does not know anything about these IPs, though, so it will not NAT
them for outbound internet traffic. To achieve that an iptables rule is used
to masquerade (aka SNAT - to make it seem as if packets came from the `Node`
itself) traffic that is bound for IPs outside the GCE project network
(10.0.0.0/8).
```shell
iptables -t nat -A POSTROUTING ! -d 10.0.0.0/8 -o eth0 -j MASQUERADE
```
Lastly IP forwarding is enabled in the kernel (so the kernel will process
packets for bridged containers):
```shell
sysctl net.ipv4.ip_forward=1
```
The result of all this is that all `Pods` can reach each other and can egress
traffic to the internet.
### Jaguar ### Jaguar
[Jaguar](https://gitlab.com/sdnlab/jaguar) is an open source solution for Kubernetes's network based on OpenDaylight. Jaguar provides overlay network using vxlan and Jaguar CNIPlugin provides one IP address per pod. [Jaguar](https://gitlab.com/sdnlab/jaguar) is an open source solution for Kubernetes's network based on OpenDaylight. Jaguar provides overlay network using vxlan and Jaguar CNIPlugin provides one IP address per pod.