/proc | environ, limits, status

By OK -
Let's say you want to look at what /proc can tell you about your login shell. The first thing you probably want to do is display your shell's process ID.
$ echo $$
8009

$ cd 8009
$ ls -l
total 0
dr-xr-xr-x 2 shs staff   0 Aug 17 12:52 attr
-r-------- 1 shs staff   0 Aug 17 12:52 auxv
-r--r--r-- 1 shs staff   0 Aug 17 12:52 cmdline
-rw-r--r-- 1 shs staff   0 Aug 17 12:52 coredump_filter
-r--r--r-- 1 shs staff   0 Aug 17 12:52 cpuset
lrwxrwxrwx 1 shs staff   0 Aug 17 12:52 cwd -> /proc/8009
-r-------- 1 shs staff   0 Aug 17 12:52 environ
lrwxrwxrwx 1 shs staff   0 Aug 17 12:52 exe -> /bin/bash
dr-x------ 2 shs staff   0 Aug 17 12:52 fd
dr-x------ 2 shs staff   0 Aug 17 12:52 fdinfo
-r-------- 1 shs staff   0 Aug 17 12:52 io
-r--r--r-- 1 shs staff   0 Aug 17 12:52 limits
-rw-r--r-- 1 shs staff   0 Aug 17 12:52 loginuid
-r--r--r-- 1 shs staff   0 Aug 17 12:52 maps
-rw------- 1 shs staff   0 Aug 17 12:52 mem
-r--r--r-- 1 shs staff   0 Aug 17 12:52 mounts
-r-------- 1 shs staff   0 Aug 17 12:52 mountstats
-rw-r--r-- 1 shs staff   0 Aug 17 12:52 oom_adj
-r--r--r-- 1 shs staff   0 Aug 17 12:52 oom_score
lrwxrwxrwx 1 shs staff   0 Aug 17 12:52 root -> /
-r--r--r-- 1 shs staff   0 Aug 17 12:52 schedstat
-r--r--r-- 1 shs staff   0 Aug 17 12:52 smaps
-r--r--r-- 1 shs staff   0 Aug 17 12:52 stat
-r--r--r-- 1 shs staff   0 Aug 17 12:52 statm
-r--r--r-- 1 shs staff   0 Aug 17 12:52 status
dr-xr-xr-x 3 shs staff   0 Aug 17 12:52 task
-r--r--r-- 1 shs staff   0 Aug 17 12:52 wchan
Some of these files are easy to use. Others require a lot more effort. The stat file provides information about a process' status, but represents the information in this format:
$ cat stat
8009 (bash) S 8008 8009 8009 34816 9706 4194304 5516 51685 0 1 6 8 37 47 15 0 1 
0 1831964390 4898816 370 4294967295 134508544 135222164 3215953072 3215951
908 10765314 0 65536 3686404 1266761467 3225587569 0 0 17 2 0 0 0
The status file is much easier to use. It provides the same kind of information as stat but in a friendlier format.
$ cat status
Name:   bash
State:  S (sleeping)
SleepAVG:       98%
Tgid:   8009
Pid:    8009
PPid:   8008
TracerPid:      0
Uid:    263     263     263     263
Gid:    100     100     100     100
FDSize: 256
Groups: 100
VmPeak:     4784 kB
VmSize:     4784 kB
VmLck:         0 kB
VmHWM:      1476 kB
VmRSS:      1476 kB
VmData:      316 kB
VmStk:        88 kB
VmExe:       700 kB
VmLib:      1544 kB
VmPTE:        28 kB
StaBrk: 08851000 kB
Brk:    08893000 kB
StaStk: bfaf8cb0 kB
ExecLim:        080f6000
Threads:        1
SigQ:   0/32375
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000010000
SigIgn: 0000000000384004
SigCgt: 000000004b813efb
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
Cpus_allowed:   0000000f
Mems_allowed:   1
Some of this information is very straightforward -- the name of the process (bash), the process ID and parent process ID. You should be easily able to pick out the UID and GID.
It should come as no surprise that our process is sleeping. At any time, most processes are sleeping and, though we're obviously using the shell when we run this command, we're running another process within the shell. We can also see that our shell is sleeping 98% of the time.

$ cat limits
Limit                     Soft Limit           Hard Limit           Units
Max cpu time              unlimited            unlimited            seconds
Max file size             unlimited            unlimited            bytes
Max data size             unlimited            unlimited            bytes
Max stack size            10485760             unlimited            bytes
Max core file size        unlimited            unlimited            bytes
Max resident set          unlimited            unlimited            bytes
Max processes             50                   50                   processes
Max open files            1024                 1024                 files
Max locked memory         32768                32768                bytes
Max address space         unlimited            unlimited            bytes
Max file locks            unlimited            unlimited            locks
Max pending signals       32375                32375                signals
Max msgqueue size         819200               819200               bytes
Max nice priority         0                    0
Max realtime priority     0                    0
The environ file shows some details about our operational environment -- such as our search path.
$ cat environ
USER=shsLOGNAME=shsHOME=/home/staff  /shsPATH=/usr/local/bin:/bin:/usr/binMAIL=
/var/mail/shsSHELL=/bin/bashSSH_CLIENT=10.20.30.111 8506 22SSH_CONNECTION=10.20.
30.111 8506 192.168.0.12 22SSH_TTY=/dev/pts/0TERM=xterm
Another interesting file to look at is the io file. As you can see, it's reporting on characters read and written. Note the changes between the first and second running.
$ cat io
rchar: 1953940
wchar: 57247
syscr: 1791
syscw: 917
read_bytes: 8192
write_bytes: 8192
cancelled_write_bytes: 4096
$ cat io
rchar: 1955293
wchar: 57370
syscr: 1804
syscw: 921
read_bytes: 8192
write_bytes: 8192
cancelled_write_bytes: 4096





Comments

Post a Comment

Popular posts from this blog

HAproxy logging

By OK -
ubuntu@ubuntu:/etc/haproxy$ cat /etc/rsyslog.d/haproxy.conf # Create an additional socket in haproxy's chroot in order to allow logging via # /dev/log to chroot'ed HAProxy processes $ModLoad imudp $UDPServerRun 514 local0.* -/var/log/haproxy-0.log local1.* -/var/log/haproxy-1.log ### keep logs in localhost ## $AddUnixListenSocket /var/lib/haproxy/dev/log ------------------- ubuntu@ubuntu:/etc/haproxy$ cat /etc/haproxy/haproxy.cfg global chroot /var/lib/haproxy user haproxy group haproxy log 127.0.0.1   local0         log 127.0.0.1   local1 notice daemon frontend www     bind 192.168.40.128:8282    # haproxy public IP     default_backend as-backend    # backend used backend as-backend    balance leastconn    mode http  server as1 192.168.40.128:8082 check    # application srv 1 defaults log ...
Read more

teamcity Automatic Agent Start under Linux

By OK -
Automatic Agent Start under Linux To run agent automatically on the machine boot under Linux, configure daemon process with the  agent.sh start  command to start it and  agent.sh stop  command to stop it. Refer to an example procedure below: 1. Navigate to the services start/stop services scripts directory: cd /etc/init.d/ 2. Open the build agent service script: sudo vim buildAgent 3. Paste the following into the file : #!/bin/sh ### BEGIN INIT INFO # Provides: TeamCity Build Agent # Required-Start: $remote_fs $syslog # Required-Stop: $remote_fs $syslog # Default-Start: 2 3 4 5 # Default-Stop: 0 1 6 # Short-Description: Start build agent daemon at boot time # Description: Enable service provided by daemon. ### END INIT INFO #Provide the correct user name: USER="agentuser" case "$1" in start) su - $USER -c "cd BuildAgent/bin ; ./agent.sh start" ;; stop) su - $USER -c "cd BuildAgent/bin ; ./agent....
Read more

NFS mount add in fstab _netdev instead of default | firewall-cmd --list-all

By OK -
Redhat recommends us to add  _netdev  option for NFS file system in /etc/fstab. So that they can be mounted after starting the networking service. Alternative ways to refer to partitions: Label : LABEL=label Network ID Samba : //server/share NFS : server:/share SSHFS : sshfs#user@server:/share Device : /dev/sdxy (not recommended) Example #1 //192.168.1.134/share_name /mnt/share_name cifs username=server_user,password=server_password,_netdev 0 0 ^ Path to your share ^ Mountpoint ^ Username ^ Password ^ See note A Note A: The  _netdev  options makes sure the mount is only attempted AFTER a network connection has been established. Example #2 10.10.10.1:/vol1/fs1 /data nfs defaults,_netdev 0 0 ============================ [root@localhost ~]# firewall-cmd --list-all public   target: default   icmp-block-inversion: no   interfaces:   sources:   services: dhcpv6-client high-availabi...
Read more