Upstream Load Balancing
This article covers Pomerium built-in load balancing capabilities in presence of multiple upstream servers.
Multiple Upstream Servers
You may specify multiple servers for your upstream application, and Pomerium would load balance user requests between them.
routes:
- from: https://myapp.localhost.pomerium.io
to:
- http://myapp-srv-1:8080
- http://myapp-srv-2:8080
In the presence of multiple upstream servers, make sure to specify either an active or passive health check, or both, to avoid requests being served to an unhealthy backend.
Active Health Checks
Active health checks issue periodic requests to each upstream to determine its health. See Health Checking for a comprehensive overview.
HTTP Example
routes:
- from: https://myapp.localhost.pomerium.io
to:
- http://myapp-srv-1:8080
- http://myapp-srv-2:8080
health_checks:
- timeout: 10s
interval: 60s
healthy_threshold: 1
unhealthy_threshold: 2
http_health_check:
path: '/'
TCP Example
routes:
- from: tcp+https://tcp-service.localhost.pomerium.io
to:
- tcp://tcp-1.local
- tcp://tcp-2.local
health_checks:
- timeout: 1s
interval: 5s
unhealthy_threshold: 3
healthy_threshold: 1
tcp_health_check:
send:
text: '50494E47' #PING
receive:
text: '504F4E47' #PONG
Passive Health Checks
Passive health check tries to deduce upstream server health based on recent observed responses. See Outlier Detection for comprehensive overview.
routes:
- from: https://myapp.localhost.pomerium.io
to:
- http://myapp-srv-1:8080
- http://myapp-srv-2:8080
outlier_detection: {}
Load Balancing Method
lb_policy
should be set to one of the values:
ROUND_ROBIN
(default)LEAST_REQUEST
and may be further configured usingleast_request_lb_config
RING_HASH
and may be further configured usingring_hash_lb_config
optionRANDOM
MAGLEV
and may be further configured usingmaglev_lb_config
option
Example
routes:
- from: https://myapp.localhost.pomerium.io
to:
- http://myapp-srv-1:8080
- http://myapp-srv-2:8080
- http://myapp-srv-3:8080
- http://myapp-srv-4:8080
- http://myapp-srv-5:8080
lb_policy: LEAST_REQUEST
least_request_lb_config:
choice_count: 2 # current envoy default
Load Balancing Weight
When a list of upstream URLs is specified in the to
field, you may append an optional load balancing weight parameter. The individual lb_policy
settings will take this weighting into account when making routing decisions.
Example
This configuration uses the default round_robin
load balancer policy but specifies different frequency of selection be applied to the upstream servers.
routes:
- from: https://myapp.localhost.pomerium.io
to:
- http://myapp-srv-1:8080,10
- http://myapp-srv-2:8080,20
- http://myapp-srv-3:8080,30
- http://myapp-srv-4:8080,20
- http://myapp-srv-5:8080,10