Load Balancing, does it actually balance?

Hi There,

We have load balancing with Cloudflare.

Earlier today, we saw a influx of traffic, it appears there was no equal steering between our origin servers and only one server was receiving traffic.

Can someone from the Cloudflare team please explain what this service actually provides? I have seen other reports of similar behaviour without a response.

Could you share some details about your Load Balancing setup (balancers, pools, origins)?

1 Like

@albert

It is a single pool with 2 origins with a weight of 0.5 each

traffic only goes to one server. the health of the pool is good.

How did you setup session affinity and zero downtime failover settings for your CF load balancer?

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CF Cookie + failback Client IP

and None for zero downtime failover.

Which origin pool steering method are you using random or hash Origin steering · Cloudflare Load Balancing docs ? Also is the Load Balancer Orange cloud enabled or orange cloud disabled for DNS only? Both options can impact your weighting of origins.

cf-lb-pool-weighting-01

Limitations

If you choose Hash for your Origin Steering or enable session affinity, these options can affect traffic distribution.

Additionally, session affinity takes precedence over any selected weight or origin steering policy.

When using DNS-only load balancing, DNS resolves may cache resolved IPs for clients and affect traffic distribution.

When you create a pool, you have to choose an option for Origin Steering:

  • Random: Sends requests to origins purely based on origin weights. Distributes traffic more accurately, but may cause requests from the same IP to hit different origins.
  • Hash: Cloudflare sends requests to origins based on a combination of origin weights and previous requests from that IP address. Ensures requests from the same IP address will hit the same origin, but actual traffic distribution may differ from origin weights.

cf-lb-pools-origin-steering-01

and Origin steering · Cloudflare Load Balancing docs

By default, all origins within a pool have a weight of 1.

If you leave each origin with the default setting and choose a Random origin steering policy, each pool will receive the same percentage of traffic. If you were to use a Hash policy, that percentage will vary based on the IP distribution of your requests.

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Origin steering = random

We have load balancing in front of our API, so the session affinity should not be active.

Proxying is turned on.

Maybe the CF Cookie + IP fallback session affinity is impacting weights Session affinity · Cloudflare Load Balancing docs ? Tried just using CF cookie?

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