Sysadmin

I want to keep under control a system where each user has an amount of filesystem quota reserved; in particular I would like to get notified if and when a user exceeds some treshold. Since I already have Monit in place in the server, I took the chance to write a small Go utility in order to retrieve the quota percentage. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 // quotachecker.go package main import ( "os" "os/exec" "regexp" "strconv" "strings" ) func main() { //a fake implementation, just for testing purpose //cmd := exec.Command("/bin/sh", "-c", "cat fakequota.txt") cmd := exec.Command("/usr/bin/repquota", "-a") stdout, err := cmd.Output() if err != nil { panic(err.Error()) } re, err := regexp.Compile("^[[:alnum:]]+\\s+--\\s+\\d+\\s+\\d+") if err != nil { panic(err.Error()) } percent_max := 0 result := strings.Split(string(stdout), "\n") for _, line := range result { match := re.MatchString(line) if !match { continue } fields := strings.Fields(line) spaceused, err := strconv.ParseInt(fields[2], 10, 64) if err != nil { panic(err.Error()) } spacetotal, err := strconv.ParseInt(fields[4], 10, 64) if err != nil { panic(err.Error()) } if spacetotal == 0 { continue } //calculate max percent used percent := int(100 * spaceused / spacetotal) if percent > percent_max { percent_max = int(percent) } } os.Exit(percent_max) } This is also an example on how to run external programs in Go and filter the output using regular expressions. ...

Long story short: you have launched your script/program but forgot to redirect the output to a file for later inspection. #!/usr/bin/python3 #sample endless running program that prints to stdout import time,datetime while True: print(datetime.datetime.now().time()) time.sleep(1) Using GNU Debugger you can re-attach to the process, then invoke the creation of a logfile and duplicate the file descriptor to make the system send the data to the new file, instead of the terminal: ...

Obiettivo vogliamo mantenere la stessa directory sincronizzata su due server linux. Questo significa che ogni aggiunta/rimozione/modifica di file in questa directory verrà automaticamente riportato sull’altro (salvo conflitti). Diamo per assunto che i due server siano raggiungibili via rete, ma per qualsiasi motivo non sia possibile collegare dello spazio disco condiviso. Implementazione Per raggiungere lo scopo, utilizzeremo il tool: csync2 su entrambi i server (che chiameremo nodo1 e nodo2), installiamo i pacchetti necessari: ...

I had a trouble with a long process running and wish to know how much I/O this process is doing, so I wrote this quick and dirty python 2.x script: import time,sys,datetime def read_stat(pid): f=open("/proc/%s/io" % pid ,"r") for line in f: if line.startswith('rchar'): rchar=line.split(':')[1] continue if line.startswith('wchar'): wchar=line.split(':')[1] continue f.close() return int(rchar),int(wchar) pid=sys.argv[1] r0,w0 = read_stat(pid) while 1: time.sleep(1) r1,w1 = read_stat(pid) print "%s\t\tr=%s\t\tw=%s" % (datetime.datetime.now().time(),r1-r0,w1-w0) r0,w0=r1,w1 You must give the process PID number as input to the script. In the output you get the read/write throughput of the process in bytes per second, for instance: ...