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trace_fsslower

The trace fsslower gadget streams file operations (open, read, write and fsync) that are slower than a threshold.

Requirements​

  • Minimum Kernel Version : 5.4

Getting started​

Running the gadget:

$ kubectl gadget run ghcr.io/inspektor-gadget/gadget/trace_fsslower:latest [flags]

Flags​

--min​

Minimum latency in µs to trace

Default value: "10000"

--pid​

Show only bind events generated by this particular PID

Default value: ""

--filesystem​

Filesystem to trace. Possible values are: btrfs, ext4, fuse, nfs, nfts3 or xfs.

Default value: "ext4"

Guide​

In this guide you'll deploy an example workload that performs some open(), read() write() and sync() calls and will trace which ones are slower than 1 ms.

Let's start the gadget before running our workload:

$ kubectl gadget run trace_fsslower:latest --podname test-trace-fsslower --filesystem ext4 --min 1000
K8S.NODE                       K8S.NAMESPACE                  K8S.PODNAME                    K8S.CONTAINERNAME              COMM                          PID              TID TID              DELTA_US   OFFSET     SIZE FILE             OP

Launch a container that will perform input/output operations:

$ kubectl run test-trace-fsslower --restart=Never --image=debian -- /bin/sh -c "apt-get update && apt-get install -y git"
pod/test-trace-fsslower created

The tool will list the I/O operations that were slower than 1ms:

$ kubectl gadget run trace_fsslower:latest --podname test-trace-fsslower --filesystem ext4 --min 1000
K8S.NODE                       K8S.NAMESPACE                  K8S.PODNAME                    K8S.CONTAINERNAME              COMM                          PID              TID TID              DELTA_US   OFFSET     SIZE FILE             OP
minikube                       default                        test-trace-fsslower            test-trace-fsslower            http                        60778            60778 60775                5832  3857488     8520 deb.debian.org_… F_WRITE
minikube                       default                        test-trace-fsslower            test-trace-fsslower            http                        60778            60778 60775                1387  6647227     1688 deb.debian.org_… F_WRITE
minikube                       default                        test-trace-fsslower            test-trace-fsslower            store                       60786            60786 60775                2085 14163567    25817 deb.debian.org_… F_WRITE
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg-preconfigu             60898            60898 60897                3077        0 9223372… #56749           F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg-preconfigu             60898            60898 60897                2464        0 9223372… #56751           F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg-preconfigu             60898            60898 60897                3393        0 9223372… config.dat-new   F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg-preconfigu             60898            60898 60897                2077        0 9223372… templates.dat-n… F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                3669        0 9223372… triggers         F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                3031        0 9223372… shlibs           F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                3348        0 9223372… symbols          F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                3064        0 9223372… md5sums          F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                3108        0 9223372… control          F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                2271        0 9223372… tmp.ci           F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                1837        0 9223372… tmp.i            F_FSYNC
minikube                       default                        test-trace-fsslower            test-trace-fsslower            dpkg                        60985            60985 60849                1570        0 9223372… updates          F_FSYNC