How can I use Sticky sessions on Docker using Traefik v2.3? - docker

Question

How can I use Sticky sessions in Traefik v2.3?
When I enable the below line in my docker compose file, my docker services (e.g. http://192.168.0.1:9086) don't work.
- "traefik.http.services.mynginximage2.loadBalancer.sticky.cookie=true"
Do you have any idea why a sticky session doesn't work?
And is it possible to make a session affinity by the labels of a service?
The following is my docker compose file:
version: "3.8"
services:
traefik:
image: traefik:v2.3
deploy:
mode: global
networks:
- traefik-net
command:
#- "--log.level=DEBUG"
- "--api.insecure=true"
- "--providers.docker=true"
- "--providers.docker.exposedbydefault=false"
- "--entrypoints.web.address=:80"
- "--entrypoints.mynginximage2_ep.address=:8086"
ports:
- 80:80
- 9086:8086
- 8080:8080
volumes:
- "/var/run/docker.sock:/var/run/docker.sock:ro"
whoami:
image: "traefik/whoami"
deploy:
replicas: 2
networks:
- traefik-net
labels:
- "traefik.enable=true"
- "traefik.http.routers.whoami.entrypoints=web"
- "traefik.http.routers.whoami.rule=Host(`192.168.0.1`) || Host(`192.168.0.2`)"
#- "traefik.http.services.whoami.loadBalancer.sticky.cookie=true"
- "traefik.http.services.whoami-service.loadbalancer.server.port=80"
mynginximage2:
image: mynginximage2
deploy:
replicas: 2
networks:
- traefik-net
#ports:
# - 9080:8086
labels:
- "traefik.enable=true"
- "traefik.http.routers.mynginximage2.entrypoints=mynginximage2_ep"
- "traefik.http.routers.mynginximage2.rule=Host(`192.168.0.1`) || Host(`192.168.0.2`)"
#- "traefik.http.services.mynginximage2.loadBalancer.sticky.cookie=true"
- "traefik.http.services.mynginximage2-service.loadbalancer.server.port=8086"
networks:
traefik-net:
external: true
name: traefik-net

Answer 1

I found the issue why my Traefik routers don't work when I enable a sticky session feature.
The solution is that each service has a different cookie name. So, I added cookie names. For example:
version: "3.8"
services:
#...
whoami:
#...
labels:
- "traefik.enable=true"
- "traefik.http.routers.whoami.entrypoints=web"
- "traefik.http.routers.whoami.rule=Host(`192.168.0.1`) || Host(`192.168.0.2`)"
- "traefik.http.services.whoami-service.loadBalancer.sticky.cookie=true"
- "traefik.http.services.whoami-service.loadBalancer.sticky.cookie.name=whoami_cookie_name"
- "traefik.http.services.whoami-service.loadbalancer.server.port=80"
mynginximage2:
#...
labels:
- "traefik.enable=true"
- "traefik.http.routers.mynginximage2.entrypoints=mynginximage2_ep"
- "traefik.http.routers.mynginximage2.rule=Host(`192.168.0.1`) || Host(`192.168.0.2`)"
- "traefik.http.services.mynginximage2-service.loadBalancer.sticky.cookie=true"
- "traefik.http.services.mynginximage2-service.loadBalancer.sticky.cookie.name=mynginximage2_cookie_name"
- "traefik.http.services.mynginximage2-service.loadbalancer.server.port=8086"
#...