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Bug 1744559

Summary:	netstat -anl runs very slow when there are many socket established
Product:	Red Hat Enterprise Linux 6	Reporter:	w
Component:	net-tools	Assignee:	Michal Ruprich <mruprich>
Status:	CLOSED WONTFIX	QA Contact:	qe-baseos-daemons
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	6.8	CC:	thozza
Target Milestone:	rc	Keywords:	Reopened
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-08-26 08:56:14 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description w 2019-08-22 12:30:03 UTC

Description of problem:
netstat -ant runs very slow when there are many socket established. which i run netstat command in docker container.


Version-Release number of selected component (if applicable):

net-tools-1.60-114.el6.x86_64


How reproducible:

running a docker container which the centos6 images in the Centos7 host. then create as many as socket connections.

runs netstat -ant will be very slow


Steps to Reproduce:
1. Find an CenOS7/RHEL7 host.
2. Install docker
3. create a docker container with centos:6

docker run  -tid -p 8080:8080 --ulimit nofile=102400:102400 centos:6 bash 

4.  exec into the container

docker exec -ti <contaienr-id> bash

5. create as many as socket connections(about 28000+ )

6. run netstat  commmand.

time netstat -anl | wc -l 

Actual results:
# time netstat -anl | wc -l 
28005

real	0m9.900s
user	0m0.096s
sys	0m9.793s

about 9 seconds, very slow.

Expected results: (using the new version of net-tools, which i build by myself in container)

# time ./netstat -anl | wc -l
28005

real	0m0.105s
user	0m0.065s
sys	0m0.044s

the command runs very quickly.

Additional info:

I debug this issue, and found that the new version of net-tools has the following patch:

https://sourceforge.net/p/net-tools/code/ci/b9963e73a1af57ecbb2e11507b6644796131aea6/

this patch use proc_fopen instead of fopen. 

```
FILE *proc_fopen(const char *name)
{
    static char *buffer;
    static size_t pagesz;
    FILE *fd = fopen(name, "r");

    if (fd == NULL)
      return NULL;

    if (!buffer) {
      pagesz = getpagesize();
      buffer = malloc(pagesz);
    }

    setvbuf(fd, buffer, _IOFBF, pagesz);
    return fd;
}
```

Can RHEL update this net-tools packages in RHEL6?

Comment 2 RHEL Program Management 2019-08-23 10:04:56 UTC

Development Management has reviewed and declined this request. You may appeal this decision by reopening this request.

Comment 3 w 2019-08-26 06:42:26 UTC

I think that there are still many user run container using centos:6 images in the CentOS7/RHEL7 Hosts. So It better to backport this patch.

Comment 4 Tomáš Hozza 2019-08-26 08:56:14 UTC

(In reply to w from comment #3)
> I think that there are still many user run container using centos:6 images
> in the CentOS7/RHEL7 Hosts. So It better to backport this patch.

Hi.

Red Hat Enterprise Linux 6 transitioned to the Maintenance Support 2 Phase on May 10, 2017.  During the Maintenance Support 2, Critical impact Security Advisories (RHSAs) and SELECTED Urgent Priority Bug Fix Advisories (RHBAs) may be released as they become available.

The official life cycle policy can be reviewed here:

http://redhat.com/rhel/lifecycle

This issue does not meet the inclusion criteria. Feel free to use our customer support to escalate this request if it is important for you.

However for community members, I'm afraid that there is not much we can do in official RHEL-6 release. You can use newer major version of RHEL (e.g. 7 or 8) or rebuild e.g. Fedora package for EPEL-6, e.g. in COPR (https://copr.fedorainfracloud.org/), which is of course unsupported.

Honestly, there is no chance that this will be resolved in RHEL-6 without a strong business case.

Comment 5 w 2019-08-26 09:06:30 UTC

(In reply to Tomáš Hozza 🤓 from comment #4)
> (In reply to w from comment #3)
> > I think that there are still many user run container using centos:6 images
> > in the CentOS7/RHEL7 Hosts. So It better to backport this patch.
> 
> Hi.
> 
> Red Hat Enterprise Linux 6 transitioned to the Maintenance Support 2 Phase
> on May 10, 2017.  During the Maintenance Support 2, Critical impact Security
> Advisories (RHSAs) and SELECTED Urgent Priority Bug Fix Advisories (RHBAs)
> may be released as they become available.
> 
> The official life cycle policy can be reviewed here:
> 
> http://redhat.com/rhel/lifecycle
> 
> This issue does not meet the inclusion criteria. Feel free to use our
> customer support to escalate this request if it is important for you.
> 
> However for community members, I'm afraid that there is not much we can do
> in official RHEL-6 release. You can use newer major version of RHEL (e.g. 7
> or 8) or rebuild e.g. Fedora package for EPEL-6, e.g. in COPR
> (https://copr.fedorainfracloud.org/), which is of course unsupported.
> 
> Honestly, there is no chance that this will be resolved in RHEL-6 without a
> strong business case.

Thank you for the information.