Envoy: Reload configuration without quit process

[odg0318]

Title: Reloading configuration without quit envoy process

Description:

I try to replace nginx with envoy as front proxy. How can I reload configuration without fully restarting envoy process? I read some documentations about hot restart, which seems like working to fork a new process and replace old process with new one. I cannot find a way to reload configuration like nginx -s reload in below links.
Is there a way to reload configuration like nginx without extra starter?

Relevant Links

http://nginx.org/en/docs/beginners_guide.html#control
http://nginx.org/en/docs/control.html

[mattklein123]

Envoy does not work in quite the same way. It uses a dynamic configuration system called xDS. One of the xDS options is to watch configuration files on disk and reload them.

See https://www.envoyproxy.io/docs/envoy/latest/configuration/overview/v2_overview and https://www.envoyproxy.io/docs/envoy/latest/api-v2/api/v2/core/config_source.proto#core-configsource

[odg0318]

@mattklein123 I already read the documentation you refered. As I undertand, I can reload(actually service discovery) ti configure target hosts as upstream not total configuration.
Please let me know something wrong I am saying

[stale[bot]]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or other activity occurs. Thank you for your contributions.

[stale[bot]]

This issue has been automatically closed because it has not had activity in the last 37 days. If this issue is still valid, please ping a maintainer and ask them to label it as "help wanted". Thank you for your contributions.

[aclowkey]

What would be the easiest way to reload configuration similar to what "nginx -s reload" does?
I read about hot restart but it didn't find any usage guide..

[dio]

@aclowkey do you think file based xDS config will help? e.g. https://medium.com/grensesnittet/file-based-dynamic-configuration-of-routes-in-envoy-proxy-6234dae968d2

Or you want to reload the bootstrap config as well?

[aclowkey]

I need to reload the clusters and route_config parts.
Looks like both can be configured as dynamic resources.
Thank you @dio

[aclowkey]

@dio It's actually not enough.
I want to have dynamic clusters, i.e. add services dynamically each with their own cluster.
The docs say that the cluster proto is for one upstream cluster, this means I need to generate dynamic list for the cluster resources. So either I'm missing something or it's not possible.

EDIT:
I read there is CDS - It sounds good, can it be configured with files like EDS? I didn't find the reference