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Today, I will talk to you about how to analyze the disk quota of overlay2 storage drivers, which may not be well understood by many people. in order to make you understand better, the editor has summarized the following for you. I hope you can get something according to this article.

Why use overlay2?

The default storage driver on docker centos is devicemapper's loop-lvm mode, which simulates block devices with files and is not recommended for production.

Direct lvm is not an out-of-the-box mode and doesn't bother to configure it.

The most important thing is that device mapper does not work in the case of docker in docker. A typical scenario is that when using drone, building a docker image will not work properly.

Excessive number of overlay storage driver layers will result in too many file links and may deplete inode

So at present, overlay2 is a better choice.

Kernel

If you use a low kernel, you may not be able to run some other basic FROM images, such as running FROM ubuntu images on centos systems with overlay2 (not necessarily).

We provide a free kernel rpm package here, which has been running in our production environment for nearly a year without any problems.

Using the xfs file system

It is impossible to limit the size of each container to 10 gigabytes without using xfs, and a misoperation of a container may result in a complete occupation of the machine disk.

We used lvm to get a partition to make the xfs file system, and of course you don't need lvm.

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If which lvs & > / dev/null; then

Echo ""; echo-e "Remove last docker lv and mount."

Lvremove k8s/docker-y

Lvcreate-y-n docker k8s-L 100G

Mkfs.xfs-n ftype=1-f / dev/mapper/k8s-docker

Mkdir-p / var/lib/docker

Mount-o pquota,uqnoenforce / dev/mapper/k8s-docker / var/lib/docker

Echo-e "/ dev/mapper/k8s-docker / var/lib/docker xfs defaults,pquota 0" > > / etc/fstab

Fi

If overlay2 does not do some special operations, cadvisor cannot monitor how many disks are actually used in the container. It can only be monitored normally through xfs and quota configuration.

Configure to use overlay2 1

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# cat / etc/docker/daemon.json

{

"storage-opts": [

"overlay2.override_kernel_check=true"

"overlay2.size=10G"

]

"log-driver": "json-file"

"log-opts": {

"max-size": "10m"

}

}

Systemctl daemon-reload systemctl restart docker

In this way, the disk size of each container can be limited to 10G.

After reading the above, do you have any further understanding of how to analyze the disk quota of overlay2 storage drivers? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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