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docs: add notes about not upgrading LB config (Azure#3884)
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jackfrancis authored and penggu committed Oct 28, 2020
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2 changes: 1 addition & 1 deletion docs/topics/clusterdefinitions.md
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Expand Up @@ -69,7 +69,7 @@ $ aks-engine get-versions
| kubeReservedCgroup | no | The name of a systemd slice to create for containment of both kubelet and the container runtime. When this value is a non-empty string, a file will be dropped at `/etc/systemd/system/$KUBE_RESERVED_CGROUP.slice` creating a systemd slice. Both kubelet and docker will run in this slice. This should not point to an existing systemd slice. If this value is unspecified or specified as the empty string, kubelet and the container runtime will run in the system slice by default. |
| kubernetesImageBase | no | Specifies the default image base URL (everything preceding the actual image filename) to be used for all kubernetes-related containers such as hyperkube, cloud-controller-manager, kube-addon-manager, etc. e.g., `k8s.gcr.io/` |
| loadBalancerSku | no | Sku of Load Balancer and Public IP. Candidate values are: `basic` and `standard`. If not set, it will be default to "standard". NOTE: Because VMs behind standard SKU load balancer will not be able to access the internet without an outbound rule configured with at least one frontend IP, AKS Engine creates a Load Balancer with an outbound rule and with agent nodes added to the backend pool during cluster creation, as described in the [Outbound NAT for internal Standard Load Balancer scenarios doc](https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-outbound-rules-overview#outbound-nat-for-internal-standard-load-balancer-scenarios) |
| loadBalancerOutboundIPs | no | Number of outbound IP addresses (e.g., 3) to use in Standard LoadBalancer configuration. If not set, AKS Engine will configure a single outbound IP address. You may want more than one outbound IP address if you are running a large cluster that is processing lots of connections. See [here](https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-outbound-connections#multifesnat) for more documentation about how adding more outbound IP addresses can increase the number of SNAT ports available for use by the Standard Load Balancer in your cluster. |
| loadBalancerOutboundIPs | no | Number of outbound IP addresses (e.g., 3) to use in Standard LoadBalancer configuration. If not set, AKS Engine will configure a single outbound IP address. You may want more than one outbound IP address if you are running a large cluster that is processing lots of connections. See [here](https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-outbound-connections#multifesnat) for more documentation about how adding more outbound IP addresses can increase the number of SNAT ports available for use by the Standard Load Balancer in your cluster. Note: this value is only configurable at cluster creation time, it can not be changed using `aks-engine upgrade`.|
| networkPlugin | no | Specifies the network plugin implementation for the cluster. Valid values are:<br>`"azure"` (default), which provides an Azure native networking experience <br>`"kubenet"` for k8s software networking implementation. <br> `"flannel"` for using CoreOS Flannel <br> `"cilium"` for using the default Cilium CNI IPAM (requires the `"cilium"` networkPolicy as well)<br> `"antrea"` for using the Antrea network plugin (requires the `"antrea"` networkPolicy as well) |
| networkPolicy | no | Specifies the network policy enforcement tool for the cluster (currently Linux-only). Valid values are:<br>`"calico"` for Calico network policy.<br>`"cilium"` for cilium network policy (uses the `"cilium"` networkPlugin exclusively).<br> `"antrea"` for Antrea network policy (uses the `"antrea"` networkPlugin exclusively).<br> `"azure"` (experimental) for Azure CNI-compliant network policy (note: Azure CNI-compliant network policy requires explicit `"networkPlugin": "azure"` configuration as well).<br>See [network policy examples](../../examples/networkpolicy) for more information. |
| privateCluster | no | Build a cluster without public addresses assigned. See `privateClusters` [below](#feat-private-cluster). |
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4 changes: 4 additions & 0 deletions docs/topics/upgrade.md
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Expand Up @@ -176,6 +176,10 @@ For each node, the cluster will follow the same process described in the section

## Frequently Asked Questions

### Can I use `aks-engine upgrade` to upgrade all possible cluster configurations in an existing cluster?

No! `aks-engine upgrade` was designed to exclusively update the Kubernetes version running on a cluster, without affecting any other cluster config (especially IaaS resources). Because under the hood `aks-engine upgrade` is actually removing and adding new VMs, various configuration changes *may* be delivered to the new VMs (such as the VM size), but these changes should be considered experimental and thoroughly tested in a staging environment before being integrated into a production workflow. Specifically, changes to the VNET, Load Balancer, and other network-related configuration are not supported as modifiable by `aks-engine upgrade`. If you need to change the Load Balancer config, for example, you will need to build a new cluster.

### When should I use `aks-engine upgrade --control-plane-only`?

We actually recommend that you *only* use `aks-engine upgrade --control-plane-only`. There are a few reasons:
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