The sysctl is a Unix interface used to modify variables that the kernel uses to determine behavior. There are two ways to work with sysctl: by directly reading and modifying files in /proc/sys and by using the sysctl program supplied with most distributions. The regedit interface is the closest parallel for Windows.
Questions tagged [sysctl]
174 questions
7
votes
2 answers
Node.js struggling with lots of concurrent connections
I'm working on a somewhat unusual application where 10k clients are precisely timed to all try to submit data at once, every 3 mins or so. This 'ab' command fairly accurately simulates one barrage in the real world:
ab -c 10000 -n 10000 -r…
stickfigure
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6
votes
1 answer
docker container: changing network kernel settings, net.core.rmem_max
I'm trying to set net.core.rmem_max=26214400 on a container
I have this docker-compose
develop:
sysctls:
- net.core.rmem_max=26214400
image: centos6
but when I do
docker-compose up -d develop
I get this error
ERROR: for…
JuanPablo
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6
votes
0 answers
How to obtain the number of mapped memory regions (mm_struct->map_count) from userspace
I'd like add the number of mapped memory regions to the status report of my daemon.
There's a number of reasons why you may want this:
There's a limit for that (vm.max_map_count) so it's good to monitor the current value.
A growing number may be a…
salmin
- 457
- 3
- 12
6
votes
1 answer
Enable Core Dumps for crashed process in macOS Sierra
I need to enable Core Dump File creation for processes which terminated by SIGABRT,SIGBUS, etс..
In previous versions of MAC OS X (include ElCapitan) to enable Code Dumps file for all processes i'm will do:
sudo sysctl -w…
aax
- 349
- 2
- 8
6
votes
1 answer
Calling "sysctlbyname(...)" with "hw.machine" flag in iOS9
Following WWDC 2015 session "703 Privacy and Your App", there is changes using sysctl. And now there we will no longer be able to call kern.proc, kern.procargs, kern.procargs2 and see data from any other processes then one's self. It's a quite legit…
topsky
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- 12
5
votes
2 answers
Default /etc/sysctl.conf settings for Mac OS X Snow Leopard?
I tried to install PostgreSQL 9.1.2 for Mac OS X 10.6 and it asked me to edit the sysctl.conf file inside the /etc/ directory, so it could use more of the shared memory PostgreSQL was asking for.
I went ahead and edited the file, saved it, rebooted…
Mur Quirk
- 171
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5
votes
0 answers
What is NodeSysctlChange node event from sysctl-monitor
I have a GKE cluster where all of my nodes get the following events constantly:
LAST SEEN TYPE REASON OBJECT MESSAGE
29m Warning NodeSysctlChange …
Mugen
- 8,301
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5
votes
0 answers
Getting CPU usage of a specific process on iOS4
I am trying to get CPU usage of various processes (cpu ticks) from a background application running on iOS4 using Apple SDK. This is done completely with users' consents so there is nothing unethical here.
I have used sysctl to get process list but…
MANDAR
- 71
- 4
5
votes
3 answers
Ansible: Failed to reload sysctl: sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory
I'm setting up kubernetes cluster with ansible. I get the following error when trying to enable kernel IP routing:
Failed to reload sysctl: sysctl: cannot stat /proc/sys/net/bridge/bridge-nf-call-iptables: No such file or directory
Is this a bug in…
Tuomas Toivonen
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5
votes
5 answers
Change congestion control algorithms per connection
The command 'sysctl' in linux as of now changes the congestion control algorithm globally for the entire system. But congestion control, where the TCP window size and other similar parameters are varied, are normally done per TCP connection. So my…
Hrishikesh Murali
- 99
- 1
- 5
4
votes
1 answer
OSX Mojave sysctl -p illegal
14 "Mojave" on my macbook and I am trying to increase the fs.inotify.max_user_watches value in /etc/sysctl.conf (to solve another problem). To conclude this rite I need to run sudo sysctl -p /etc/sysctl.conf. But I get
"illegal option -- p"
When I…
nemo
- 593
- 2
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4
votes
1 answer
Whitelisting sysctls for containers in Kubernetes Kind
I'm trying to deploy a container in a Kubernetes Kind cluster. The container I'm trying to deploy needs a couple of sysctls flags to be set.
The deployment fails with
forbidden sysctl: "kernel.msgmnb" not whitelisted
UPDATE
I have since added a…
Tudor Vintilescu
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4
votes
2 answers
Setting multiple values in sysctl with Ansible
I have a playbook with several tasks setting values to sysctl. Instead of having a task for each setting, how can I set all the values with one task, using the sysctl module?
Playbook snippet:
- name: Set tcp_keepalive_probes in sysctl
become:…
Pedro Gordo
- 1,825
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- 45
4
votes
2 answers
Linux shmmax and shmall - how to set correct unit?
I have a server which has 16 GB memory.
Now I need to set my shmmax and shmall, because the server default is (checked with ipcs -l)
------ Messages Limits --------
max queues system wide = 32000
max size of message (bytes) = 8192
default max size…
Frank Liao
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4
votes
2 answers
Swift sysctl get integer
I'm trying to make an application that reads system information (on MacOS) and I've been able to read sysctl STRINGS like so:
func cpu() -> String {
var size = 0
sysctlbyname("machdep.cpu.brand_string", nil, &size, nil, 0)
var machine =…
user265889
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