xds: Allow child of cluster_impl LB to change #10091
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
@ejona86 FYI |
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
temawi
force-pushed
the
clusterimpl-graceful-switch
branch
from
00995af to
d50d989
Compare
|
Everything looks good except that GracefulSwitchLoadBalancer is marked experimental. Since ClusterImplLoadBalancer isn't, I believe that it isn't supposed to depend on an experimental class. |
|
I've added GracefulSwitchLoadBalancer to the top of the stabilization agenda. |
It's already being used by several other LBs, so I think we can use it here. +1 to your other comment about stabilizing it. |
larry-safran
approved these changes
Apr 21, 2023
This is apples and oranges. We can use experimental APIs, because we can change the callers at the same time as breaking the API. That's why it is safe(r) for us to use ClusterImplLoadBalancer is not experimental. The class is not exposed at all. The only way the class would be exposed is via the LB registry, and its name there is also experimental. And the LoadBalancer API itself is experimental. |
ejona86
approved these changes
Apr 21, 2023
ejona86
reviewed
Apr 21, 2023
temawi
added a commit
to temawi/grpc-java
that referenced
this pull request
Apr 24, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
|
While the problem is explained correctly, the premise is off. There is no alternating between |
temawi
added a commit
to temawi/grpc-java
that referenced
this pull request
Apr 25, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
temawi
added a commit
to temawi/grpc-java
that referenced
this pull request
Apr 25, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
temawi
added a commit
that referenced
this pull request
Apr 25, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
temawi
added a commit
that referenced
this pull request
Apr 25, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
temawi
added a commit
that referenced
this pull request
Apr 25, 2023
Under normal conditions the child LB of `ClusterImplLoadBalancer` does not fluctuate, based on the field used to configure load balancing in the xDS `Cluster` proto it is either: 1. `WrrLocalityLoadBalancer` if the newer `load_balancing_policy` field is used 2. `WeightedTargetLoadBalancer` if the legacy `lb_policy` field is used `ClusterImplLoadBalancer` currently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic. To address this, `ClusterImplLoadBalancer` will now use `GracefulSwitchLoadBalancer` and makes sure if the child policy changes the correct LB implementation is switched to.
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Under normal conditions the child LB ofClusterImplLoadBalancerdoes not fluctuate, based on the field used to configure load balancing in the xDSClusterproto it is either:1.WrrLocalityLoadBalancerif the newerload_balancing_policyfield is used2.
WeightedTargetLoadBalancerif the legacylb_policyfield is used(The premise set here is off, see comment)
ClusterImplLoadBalancercurrently assumes that this child does not change and so does not change the child LB when the name resolver sends an update. If the control plane does switch to using a different field for LB config, that update will have an LB config meant for the other child LB type. This will result in a ClassCastException and a channel panic.To address this,
ClusterImplLoadBalancerwill now useGracefulSwitchLoadBalancerand makes sure if the child policy changes the correct LB implementation is switched to.Closes #10006