aa918255d9
This patch is required for the updated version of libnetwork and entails two minor changes. First, it uses the new libnetwork.NetworkDeleteOptionRemoveLB option to the network.Delete() method to automatically remove the load balancing endpoint for ingress networks. This allows removal of the deleteLoadBalancerSandbox() function whose functionality is now within libnetwork. The second change is to allocate a load balancer endpoint IP address for all overlay networks rather than just "ingress" and windows overlay networks. Swarmkit is already performing this allocation, but moby was not making use of these IP addresses for Linux overlay networks (except ingress). The current version of libnetwork makes use of these IP addresses by creating a load balancing sandbox and endpoint similar to ingress's for all overlay network and putting all load balancing state for a given node in that sandbox only. This reduces the amount of linux kernel state required per node. In the prior scheme, libnetwork would program each container's network namespace with every piece of load balancing state for every other container that shared *any* network with the first container. This meant that the amount of kernel state on a given node scaled with the square of the number of services in the cluster and with the square of the number of containers per service. With the new scheme, kernel state at each node scales linearly with the number of services and the number of containers per service. This also reduces the number of system calls required to add or remove tasks and containers. Previously the number of system calls required grew linearly with the number of other tasks that shared a network with the container. Now the number of system calls grows linearly only with the number of networks that the task/container is attached to. This results in a significant performance improvement when adding and removing services to a cluster that already heavily loaded. The primary disadvantage to this scheme is that it requires the allocation of an additional IP address per node per subnet for every node in the cluster that has a task on the given subnet. However, as mentioned, swarmkit is already allocating these IP addresses for every node and they are going unused. Future swarmkit modifications should be examined to only allocate said IP addresses when nodes actually require them. Signed-off-by: Chris Telfer <ctelfer@docker.com> Upstream-commit: 8e0f6bc90351525f3e52f3bc357378fcccccdd27 Component: engine