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Docker limited number of tcp connection

Description

I have did a tcp connect test, start a tcp server in a host, and start other host run containers in containers connect to tcp server.

when total number of connections (sum all connectoin number of all containers) almost reach to 65535 (eg: 64512 just now), the other tcp connection throw exception “connection timeout”.

I tried to use 3 hosts without docker to connect tcp server each 60K connections is ok, it said that the tcp server do 180K connections is ok.

Steps to reproduce the issue:

  1. start tcp server in host A
  2. start container C1 in host B
  3. start 60K connection to tcp server in C1
  4. start container C2 in host B
  5. start 60K connection to tcp server in C2

Describe the results you received:

total tcp connection more less than 120K

Describe the results you expected:

each 60K connection in two container total 120K connection made.

Additional information you deem important (e.g. issue happens only occasionally):

host configurations:

in host

root@debian:~# ulimit -n
800000

net.ipv4.ip_local_port_range = 5000     65535
net.ipv4.tcp_mem = 8388608      12582912        16777216
net.ipv4.netfilter.ip_conntrack_max = 1000000
net.netfilter.nf_conntrack_max = 1000000
net.netfilter.nf_conntrack_count = 64515
net.nf_conntrack_max = 1000000

                   total       used       free     shared    buffers     cached
Mem:          986M       808M       178M       8.5M       5.0M       132M
-/+ buffers/cache:       670M       316M
Swap:         1.0G       872K       1.0G

in container

 ulimit -n
800000

net.ipv4.ip_local_port_range = 1024     65535
net.ipv4.netfilter.ip_conntrack_max = 1000000
net.netfilter.nf_conntrack_max = 1000000
net.netfilter.nf_conntrack_count = 6653

Output of docker version:

Client:
 Version:      17.03.1-ce
 API version:  1.27
 Go version:   go1.7.5
 Git commit:   c6d412e
 Built:        Mon Mar 27 17:07:28 2017
 OS/Arch:      linux/amd64

Server:
 Version:      17.03.1-ce
 API version:  1.27 (minimum version 1.12)
 Go version:   go1.7.5
 Git commit:   c6d412e
 Built:        Mon Mar 27 17:07:28 2017
 OS/Arch:      linux/amd64
 Experimental: false

Output of docker info:

Containers: 6
 Running: 2
 Paused: 0
 Stopped: 4
Images: 15
Server Version: 17.03.1-ce
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 27
 Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins: 
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 4ab9917febca54791c5f071a9d1f404867857fcc
runc version: 54296cf40ad8143b62dbcaa1d90e520a2136ddfe
init version: 949e6fa
Kernel Version: 3.16.0-4-amd64
Operating System: Debian GNU/Linux 8 (jessie)
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 986.9 MiB
Name: debian
ID: GEUG:DUKW:FDXQ:DFUP:GOI7:S4YO:GIH7:RX55:SQ6Z:ZZFQ:MEXB:2EHP
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: No memory limit support
WARNING: No swap limit support
WARNING: No kernel memory limit support
WARNING: No oom kill disable support
WARNING: No cpu cfs quota support
WARNING: No cpu cfs period support
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
1 Like

The same issue. Have you found a solution to the problem?