98 lines
3.9 KiB
Plaintext
98 lines
3.9 KiB
Plaintext
---
|
|
layout: docs
|
|
page_title: Rolling Updates to TLS for Existing Clusters on Kubernetes
|
|
description: >-
|
|
Consul Helm chart 0.16.0 and later supports TLS communication within clusters. Follow the instructions to trigger rolling updates for consul-k8s without causing downtime.
|
|
---
|
|
|
|
# Rolling Updates to TLS for Existing Clusters on Kubernetes
|
|
|
|
As of Consul Helm version `0.16.0`, the chart supports TLS for communication
|
|
within the cluster. If you already have a Consul cluster deployed on Kubernetes,
|
|
you may want to configure TLS in a way that minimizes downtime to your applications.
|
|
Consul already supports rolling out TLS on an existing cluster without downtime.
|
|
However, depending on your Kubernetes use case, your upgrade procedure may be different.
|
|
|
|
## Gradual TLS Rollout without Consul Connect
|
|
|
|
If you do not use a service mesh, follow this process.
|
|
|
|
1. Run a Helm upgrade with the following config:
|
|
|
|
```yaml
|
|
global:
|
|
tls:
|
|
enabled: true
|
|
# This configuration sets `verify_outgoing`, `verify_server_hostname`,
|
|
# and `verify_incoming` to `false` on servers and clients,
|
|
# which allows TLS-disabled nodes to join the cluster.
|
|
verify: false
|
|
server:
|
|
updatePartition: <number_of_server_replicas>
|
|
```
|
|
|
|
This upgrade trigger a rolling update of `consul-k8s` components.
|
|
|
|
1. Perform a rolling upgrade of the servers, as described in
|
|
[Upgrade Consul Servers](/consul/docs/k8s/upgrade#upgrading-consul-servers).
|
|
|
|
1. Repeat steps 1 and 2, turning on TLS verification by setting `global.tls.verify`
|
|
to `true`.
|
|
|
|
## Gradual TLS Rollout with Consul Connect
|
|
|
|
Because the sidecar Envoy proxies need to talk to the Consul client agent regularly
|
|
for service discovery, we can't enable TLS on the clients without also re-injecting a
|
|
TLS-enabled proxy into the application pods. To perform TLS rollout with minimal
|
|
downtime, we recommend instead to add a new Kubernetes node pool and migrate your
|
|
applications to it.
|
|
|
|
1. Add a new identical node pool.
|
|
|
|
1. Cordon all nodes in the old pool by running `kubectl cordon`.
|
|
This command ensures Kubernetes does not schedule any new workloads on those nodes,
|
|
and instead schedules onto the new TLS-enabled nodes.
|
|
|
|
1. Create the following Helm config file for the upgrade:
|
|
|
|
```yaml
|
|
global:
|
|
tls:
|
|
enabled: true
|
|
# This configuration sets `verify_outgoing`, `verify_server_hostname`,
|
|
# and `verify_incoming` to `false` on servers and clients,
|
|
# which allows TLS-disabled nodes to join the cluster.
|
|
verify: false
|
|
server:
|
|
updatePartition: <number_of_server_replicas>
|
|
client:
|
|
updateStrategy: |
|
|
type: OnDelete
|
|
```
|
|
|
|
In this configuration, we're setting `server.updatePartition` to the number of
|
|
server replicas as described in [Upgrade Consul Servers](/consul/docs/k8s/upgrade#upgrading-consul-servers).
|
|
|
|
1. Run `helm upgrade` with the above config file.
|
|
|
|
1. At this point, all components (e.g., Consul Connect webhook and sync catalog) should be running
|
|
on the new node pool.
|
|
|
|
1. Redeploy all your Connect-enabled applications.
|
|
One way to trigger a redeploy is to run `kubectl drain` on the nodes in the old pool.
|
|
Now that the Connect webhook is TLS-aware, it adds TLS configuration to
|
|
the sidecar proxy. Also, Kubernetes should schedule these applications on the new node pool.
|
|
|
|
1. Perform a rolling upgrade of the servers described in
|
|
[Upgrade Consul Servers](/consul/docs/k8s/upgrade#upgrading-consul-servers).
|
|
|
|
1. If everything is healthy, delete the old node pool.
|
|
|
|
1. Finally, set `global.tls.verify` to `true` in your Helm config file, remove the
|
|
`client.updateStrategy` property, and perform a rolling upgrade of the servers.
|
|
|
|
-> **Note:** It is possible to do this upgrade without fully duplicating the node pool.
|
|
You could drain a subset of the Kubernetes nodes within your existing node pool and treat it
|
|
as your "new node pool." Then follow the above instructions. Repeat this process for the rest
|
|
of the nodes in the node pool.
|