Ulimits in Docker host vs container
I wasn't able to find straight answer, to this question, but here it is:
Let's say that I have a host which has max open files 1024:
[root@host]# ulimit -a
open files (-n) 1024
and a docker container running in that host with:
[root@container]# ulimit -a
open files (-n) 1048576
So will I have a problem in container if I try to open more then 1024 files? I think real limit in this case for container will be 1024 files. What do you think?
docker containers ulimit
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
add a comment |
I wasn't able to find straight answer, to this question, but here it is:
Let's say that I have a host which has max open files 1024:
[root@host]# ulimit -a
open files (-n) 1024
and a docker container running in that host with:
[root@container]# ulimit -a
open files (-n) 1048576
So will I have a problem in container if I try to open more then 1024 files? I think real limit in this case for container will be 1024 files. What do you think?
docker containers ulimit
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
add a comment |
I wasn't able to find straight answer, to this question, but here it is:
Let's say that I have a host which has max open files 1024:
[root@host]# ulimit -a
open files (-n) 1024
and a docker container running in that host with:
[root@container]# ulimit -a
open files (-n) 1048576
So will I have a problem in container if I try to open more then 1024 files? I think real limit in this case for container will be 1024 files. What do you think?
docker containers ulimit
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
I wasn't able to find straight answer, to this question, but here it is:
Let's say that I have a host which has max open files 1024:
[root@host]# ulimit -a
open files (-n) 1024
and a docker container running in that host with:
[root@container]# ulimit -a
open files (-n) 1048576
So will I have a problem in container if I try to open more then 1024 files? I think real limit in this case for container will be 1024 files. What do you think?
docker containers ulimit
docker containers ulimit
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
edited Nov 23 '18 at 7:51
informatik01
13.2k85691
13.2k85691
asked Sep 14 '17 at 5:56
os11kos11k
582618
asked Sep 14 '17 at 5:56
os11kos11k
582618
asked Sep 14 '17 at 5:56
os11kos11k
582618
582618
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
Although its a little bit late, I just want to clear the doubts about the difference in ulimit.
If you do net set the value when running the container, the ulimit value displayed within the container comes from the host OS. The question is then why are you seeing a different value when running the same command from the host?
This is because when running the command in the host, it is showing its soft limit. On the other hand, the value that the container is showing is the hard limit of the host OS. The reason for this is you are allowed to cross the soft limit. So in a sense, hard limit is actually the real limit. You can find more about ulimit in this link.
To see the hard limit just type the following command
ulimit -Hn
You will see that the values match.
N.B. You can not cross the hard limit but you can increase it if you are the root.
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
add a comment |
The real limit will be 1048576.
Have a look at the right part of this image, which shows that containers are basically just isolated processes, running on the same operating system:
As every system call in the container will be handled directly by the host OS, the ulimit that is displayed (1048576) comes directly from the host OS and that is the value that will be used.
The difference in the ulimits could have been caused by a Docker configuration, for example.
(Note that for VMs, this will be different: The guest OS might display a value of 1048576, but the open calls will in the end be handled by the host OS, which will impose the limit of 1024)
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Although its a little bit late, I just want to clear the doubts about the difference in ulimit.
If you do net set the value when running the container, the ulimit value displayed within the container comes from the host OS. The question is then why are you seeing a different value when running the same command from the host?
This is because when running the command in the host, it is showing its soft limit. On the other hand, the value that the container is showing is the hard limit of the host OS. The reason for this is you are allowed to cross the soft limit. So in a sense, hard limit is actually the real limit. You can find more about ulimit in this link.
To see the hard limit just type the following command
ulimit -Hn
You will see that the values match.
N.B. You can not cross the hard limit but you can increase it if you are the root.
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
add a comment |
Although its a little bit late, I just want to clear the doubts about the difference in ulimit.
If you do net set the value when running the container, the ulimit value displayed within the container comes from the host OS. The question is then why are you seeing a different value when running the same command from the host?
This is because when running the command in the host, it is showing its soft limit. On the other hand, the value that the container is showing is the hard limit of the host OS. The reason for this is you are allowed to cross the soft limit. So in a sense, hard limit is actually the real limit. You can find more about ulimit in this link.
To see the hard limit just type the following command
ulimit -Hn
You will see that the values match.
N.B. You can not cross the hard limit but you can increase it if you are the root.
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
add a comment |
Although its a little bit late, I just want to clear the doubts about the difference in ulimit.
If you do net set the value when running the container, the ulimit value displayed within the container comes from the host OS. The question is then why are you seeing a different value when running the same command from the host?
This is because when running the command in the host, it is showing its soft limit. On the other hand, the value that the container is showing is the hard limit of the host OS. The reason for this is you are allowed to cross the soft limit. So in a sense, hard limit is actually the real limit. You can find more about ulimit in this link.
To see the hard limit just type the following command
ulimit -Hn
You will see that the values match.
N.B. You can not cross the hard limit but you can increase it if you are the root.
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
Although its a little bit late, I just want to clear the doubts about the difference in ulimit.
If you do net set the value when running the container, the ulimit value displayed within the container comes from the host OS. The question is then why are you seeing a different value when running the same command from the host?
This is because when running the command in the host, it is showing its soft limit. On the other hand, the value that the container is showing is the hard limit of the host OS. The reason for this is you are allowed to cross the soft limit. So in a sense, hard limit is actually the real limit. You can find more about ulimit in this link.
To see the hard limit just type the following command
ulimit -Hn
You will see that the values match.
N.B. You can not cross the hard limit but you can increase it if you are the root.
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
edited Nov 25 '18 at 22:53
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
answered May 3 '18 at 0:42
Alim Ul GiasAlim Ul Gias
3,31521935
3,31521935
add a comment |
add a comment |
The real limit will be 1048576.
Have a look at the right part of this image, which shows that containers are basically just isolated processes, running on the same operating system:
As every system call in the container will be handled directly by the host OS, the ulimit that is displayed (1048576) comes directly from the host OS and that is the value that will be used.
The difference in the ulimits could have been caused by a Docker configuration, for example.
(Note that for VMs, this will be different: The guest OS might display a value of 1048576, but the open calls will in the end be handled by the host OS, which will impose the limit of 1024)
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
add a comment |
The real limit will be 1048576.
Have a look at the right part of this image, which shows that containers are basically just isolated processes, running on the same operating system:
As every system call in the container will be handled directly by the host OS, the ulimit that is displayed (1048576) comes directly from the host OS and that is the value that will be used.
The difference in the ulimits could have been caused by a Docker configuration, for example.
(Note that for VMs, this will be different: The guest OS might display a value of 1048576, but the open calls will in the end be handled by the host OS, which will impose the limit of 1024)
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
add a comment |
The real limit will be 1048576.
Have a look at the right part of this image, which shows that containers are basically just isolated processes, running on the same operating system:
As every system call in the container will be handled directly by the host OS, the ulimit that is displayed (1048576) comes directly from the host OS and that is the value that will be used.
The difference in the ulimits could have been caused by a Docker configuration, for example.
(Note that for VMs, this will be different: The guest OS might display a value of 1048576, but the open calls will in the end be handled by the host OS, which will impose the limit of 1024)
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
The real limit will be 1048576.
Have a look at the right part of this image, which shows that containers are basically just isolated processes, running on the same operating system:
As every system call in the container will be handled directly by the host OS, the ulimit that is displayed (1048576) comes directly from the host OS and that is the value that will be used.
The difference in the ulimits could have been caused by a Docker configuration, for example.
(Note that for VMs, this will be different: The guest OS might display a value of 1048576, but the open calls will in the end be handled by the host OS, which will impose the limit of 1024)
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
answered Sep 15 '17 at 6:45
user3151902user3151902
1,8261221
1,8261221
add a comment |
add a comment |
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