Description of problem: incorrect mtu in node-config.yaml on GCE Version-Release number of the following components: openshift-ansible-3.10.0-0.21.0.git.0.0b1d180.el7.noarch.rpm How reproducible: Always Steps to Reproduce: 1. set up OCP 3.10 cluster on GCE 2. check cluster Actual results: # ip link show eth0 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 42:01:0a:f0:00:05 brd ff:ff:ff:ff:ff:ff # grep mtu /etc/origin/node/node-config.yaml mtu: 8951 Expected results: # grep mtu /etc/origin/node/node-config.yaml mtu: 1410 Additional info: When a packet is larger than the MTU size that is transmitted over HTTP, the physical network router is able to break the packet into multiple packets to transmit the data. However, when a packet is larger than the MTU size is that transmitted over HTTPS, the router is forced to drop the packet. To fix this issue, adjust the MTU size within the /etc/origin/node/node-config.yaml to 50 bytes smaller than the MTU size being used by the OpenShift SDN Ethernet device. https://docs.openshift.com/container-platform/3.9/day_two_guide/environment_health_checks.html#day-two-guide-verifying_mtu
Can you provide a complete list of interfaces on the host?
[root@qe-wmeng21-master-etcd-1 ~]# grep -r mtu /etc/origin/node/ /etc/origin/node/bootstrap-node-config.yaml: mtu: 8951 /etc/origin/node/node-config.yaml: mtu: 8951 [root@qe-wmeng21-master-etcd-1 ~]# ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1460 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 42:01:0a:f0:00:04 brd ff:ff:ff:ff:ff:ff 3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default link/ether 02:42:46:1e:fa:f9 brd ff:ff:ff:ff:ff:ff 4: ovs-system: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether e6:99:c0:61:9f:fc brd ff:ff:ff:ff:ff:ff 5: br0: <BROADCAST,MULTICAST> mtu 8951 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 8a:c8:a8:4f:40:4a brd ff:ff:ff:ff:ff:ff 6: vxlan_sys_4789: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 65000 qdisc noqueue master ovs-system state UNKNOWN mode DEFAULT group default qlen 1000 link/ether be:2a:56:f1:c5:ea brd ff:ff:ff:ff:ff:ff 7: tun0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8951 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/ether ca:ec:45:c9:09:e4 brd ff:ff:ff:ff:ff:ff 9: vethf87cb036@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8951 qdisc noqueue master ovs-system state UP mode DEFAULT group default link/ether 1a:3b:d4:76:6e:5f brd ff:ff:ff:ff:ff:ff link-netnsid 1 10: veth7a30e967@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8951 qdisc noqueue master ovs-system state UP mode DEFAULT group default link/ether fe:26:f6:9a:a2:30 brd ff:ff:ff:ff:ff:ff link-netnsid 0 11: veth79ab9764@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8951 qdisc noqueue master ovs-system state UP mode DEFAULT group default link/ether 4e:68:30:0f:46:e8 brd ff:ff:ff:ff:ff:ff link-netnsid 2 12: vethe2f6f3a6@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 8951 qdisc noqueue master ovs-system state UP mode DEFAULT group default link/ether 8a:6f:48:c8:f7:95 brd ff:ff:ff:ff:ff:ff link-netnsid 3 [root@qe-wmeng21-master-etcd-1 ~]#
Need to change roles/openshift_node_group/defaults/main.yml to use openshift.node.sdn_mtu as default rather than 8951
https://github.com/openshift/openshift-ansible/pull/8046
openshift-ansible-3.10.0-0.24.0.git.0.fd7f37c.el7
Fixed. openshift-ansible-3.10.0-0.26.0.git.0.dbc127c.el7.noarch # grep mtu /etc/origin/node/node-config.yaml mtu: 1410 Operating System: Red Hat Enterprise Linux Server 7.5 (Maipo) CPE OS Name: cpe:/o:redhat:enterprise_linux:7.5:GA:server Kernel: Linux 3.10.0-862.el7.x86_64
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHBA-2018:1816