Kubernetes allows to manage large clusters which are composed of docker containers. And where is large computation power there is large amount of data throughput. However, there is still a need to spread the data throughput so it can reach and utilize particular docker container(s). This is called load balancing. Kubernetes supports two basic forms of load balancing. Internal among docker containers themselves and external for clients which call you application from outside environment - just users.
Internal Load Balancing with Kubernetes
Usual approach during the modeling of an application in kubernetes is to provide domain models for pods, replications controllers and services. Look at the great documentation if you are not aware of all these principles.
For simplification, pod is a set of docker containers which are always located on the same node. Replication controller allows and guarantees scalability. The last but not least is the service which hides all instances of pods - cre…
I try to setup nginx as a load balancer. The configuration is just a file with a lot of constrains so I need a validation. There is no online validation service, as e.g. CoreOS has, and I don't want to install nginx on my laptop as I work on a distributed app.
Docker is right approach for me. Let say I have following config:
In short, I'm going to pass nginx config to running nginx instance and look to the logs.
Put you nginx.config to the temp and start the docker image:
sudo docker run --name nginx -v /tmp/nginx.config:/etc/nginx/nginx.conf:ro -d nginx
It uses volume mapping so the command just starts a new docker container and mounts a local /tmp/nginx.config to the given in-container path. You can obviously change the volume path to your personal path. Is it working or not? Look at logs.
sudo docker logs nginx
If there is no entry, your file is fine. In the case of an error, you can see something like this:
2016/01/08 11:37:31 [emerg] 1#1: unexpected "}" in /etc/…