I run a Kubernetes cluster with version 1.5.2, setup with Kops on AWS. The setup has nothing exotic. My nodes run on m4.xlarge with 70 Gb of disk storage with 1000 iops.

I have periods where some of my nodes get crazy with iops. Here is what I see:

So du take all my iops in the docker overlay directory. Here is what the kubelet logs display:

fsHandler.go:131] du and find on following dirs took 4.22914425s: [/var/lib/docker/overlay/592c1d88d1fd115f21e8fe6f198a8a27cd44efefb9b5dc58940fbf6d7999eda3 /var/lib/docker/containers/2347d28886bc0e6b74fc326538e1483927ddeb89b38e035acd845d5db621cb79]
fsHandler.go:131] du and find on following dirs took 24.94283434s: [/var/lib/docker/overlay/81f24df3624ebf7b7e45edc38fafeb41958bc675ae57fd0126c44cb2c3a6d6d6 /var/lib/docker/containers/43d576931081500fd4cd316afe5bfc6ff2442ff20e8e8266c27e930a0a77dd34]
fsHandler.go:131] du and find on following dirs took 18.478782737s: [/var/lib/docker/overlay/422ef31413df4e76de51acaa7d6ff6f77edc65fabde88a7c70e7edad3b1e55e5 /var/lib/docker/containers/1519a33729c8fb13297358edc53fe22f0b4b684636884976dfcb67c47fbf320b]
helpers.go:101] Unable to get network stats from pid 13515: couldn't read network stats: failure opening /proc/13515/net/dev: open /proc/13515/net/dev: no such file or directory
fsHandler.go:131] du and find on following dirs took 7.971745844s: [/var/lib/docker/overlay/45b83939bd1b4ec7dfa627bb6a9eb8b89a380007f9e22a93fff2ba4054252271 /var/lib/docker/containers/f6d3387423398d7dd4fac6c19ee0a1446d0465b5f9cf90289fcd605ad28c0d6e]
fsHandler.go:131] du and find on following dirs took 5.886763577s: [/var/lib/docker/overlay/8c01a73671eedb2e62c58fa12fc2d25df58c506545b6ea048fa0db1756d19f2c /var/lib/docker/containers/1d9c0ebcc6dbbd7065923f7f81c05c0d9d710aed0d353a1bab90ce1c994dfb57]
fsHandler.go:131] du and find on following dirs took 5.714942029s: [/var/lib/docker/overlay/26213ba30a17f240a9b9756a0d23ab32550f921de533667c9ab91cfb7f10ed5b /var/lib/docker/containers/7c27c242a49d8d33cee8b2e8335dae450af13b26f010794dc83ef5750a212d0d]
fsHandler.go:131] du and find on following dirs took 6.111478835s: [/var/lib/docker/overlay/0fe2bd0feeda24699bd6d443ca126ac1a33071cdff039ae9fd9159bbef80867b /var/lib/docker/containers/ec6fb966139e9666ec0be5e13399773f1971ddd99841b84167a7463402e28d73]
fsHandler.go:131] du and find on following dirs took 2.661604836s: [/var/lib/docker/overlay/04f9d01a8863cfee26e678e938fced84f826dda6ed03626dda11b6aad6901465 /var/lib/docker/containers/a4e37aee69c7523c46c5252c1834fa3fcd5a804a7aee256a468e44b4d6bcbd64]
fsHandler.go:131] du and find on following dirs took 11.834409809s: [/var/lib/docker/overlay/4cb1476621b90e2c2ee2b1131c0e6ac62f62dc3ca418129812b487bffac1d827 /var/lib/docker/containers/5a01521cfdd3041aff128dce7353ab336ddafa60c8c0b2254fb6bae697cb1676]