On Mon, Jun 26, 2017 at 5:34 PM, Alfredo Deza <adeza@xxxxxxxxxx> wrote: > On Mon, Jun 26, 2017 at 11:52 AM, John Spray <jspray@xxxxxxxxxx> wrote: >> Hi guys, >> >> I was pondering this and wondered if you had any existing plans... >> >> For doing network testing between two remote nodes, we'll need to be >> able to spin up some sort of listener on one end, presumably via SSH >> from a third party node. > > What kind of testing warrants this type of setup? I'm talking about opening a TCP connection between two remote nodes to verify that the network connectivity is working, and probably doing this across a large set of pairs e.g. doing an all-to-all ping pong between OSD nodes. Obviously, there is just the standard `ping`, but I'm expecting that we'll want to test using actual TCP traffic in the port ranges that the OSDs would use. John >> >> I guess the choice here is whether to depend on having ceph-medic >> already installed on all the nodes (and invoke it with a special >> --receiver type argument) or whether the tool should inject its code >> over SSH (e.g. run a big fat python command line with a script in it >> over SSH). >> > > That is kind of how this works already, borrowing from ceph-deploy: it > uses SSH to connect > to remote nodes and execute either system commands or Python code. > > In what scenario using a system call or Python code will not gather > enough information that a server/client > setup would? > >> I lean towards the latter in the interests of making the deployment >> simple, but I'm not sure what the story is with e.g. selinux in >> situations like this, whether a server is going to get unhappy about >> an SSH session that tries to open ports. > > Having two processes running to check connectivity sounds a bit > complicated to handle. One of the things the tool does > is to cross-check against other nodes in the system, so this would > potentially mean running an exponential amount of > processes: for every node to each node in the cluster. > > It will be cheaper to perform those checks with either plain Python or > a system call. > > Or maybe you mean some other type of check? What are your ideas on > "network testing" ? >> >> John -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
