We are getting very frequently below message in /var/log/messages
kernel: SLUB: Unable to allocate memory on node -1 (gfp=0x8020)
In some cases followed by an allocation table
kernel: cache: sigqueue(12019:454c4ebd186d964699132181ad7367c669700f7d8991c47d4bc053ed101675bc), object size: 160, buffer size: 160, default order: 0, min order: 0
kernel: node 0: slabs: 57, objs: 23313, free: 0
kernel: node 1: slabs: 35, objs: 14315, free: 0
Ok, free is 0, but how may this be tuned?
Following is set information
OS - Centos7.3
Kernel - 3.10.0-327.36.3.el7.x86_64
Docker - 1.12.6
Kubernetes - 1.5.5
We have private cloud powered by kurbernetes, having 10 nodes; it was working fine till last month and now we are getting these alerts very frequently on every nodes, pods/container also increased in last few days.
We have enough memory
and cpu
available on each node.
Any fine tuning for these alert will be very helpful.
Additional information:
sysctl.conf
options
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_max_syn_backlog = 4096
net.core.somaxconn = 1024
net.ipv4.tcp_syncookies = 1
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.rmem_default = 65535
net.core.wmem_default = 65535
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
net.ipv4.ip_local_port_range = 1024 65535
vm.max_map_count = 262144
vm.swappiness=10
vm.vfs_cache_pressure=100
Please look at this: https://pingcap.com/blog/try-to-fix-two-linux-kernel-bugs-while-testing-tidb-operator-in-k8s/. It's a kernel bug.
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