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healthcheck_port: drop lsof in favor of awk/find

It seems lsof is a bit too heavy on the system when multiple
healthchecks are running in parallel.
So instead of calling a "big" process, let's split a bit things and get
to the filesystem directly in order to pick only the things we actually
need.

What changes:
- using /proc/net/{tcp,udp}, we get every socket matching the port
- using find with the right options, we can ensure at least one socket
  exists with the wanted inode(s)

The last part exits as soon as we have a match in order to make it
faster and less resource consuming.

Change-Id: I64776992a7e457781aa8ddaba359ef085d4cb77d
Partial-Bug: #1921714
changes/04/785004/5
Cédric Jeanneret 1 month ago
parent
commit
a072a7f07e
1 changed files with 29 additions and 11 deletions
  1. +29
    -11
      healthcheck/common.sh

+ 29
- 11
healthcheck/common.sh View File

@ -50,18 +50,36 @@ healthcheck_port () {
process=$1
shift 1
args=$@
ports=""
puser=$(get_user_from_process $process)
ports=${args// /,}
pids=$(pgrep -d ',' -f $process)
# First match exits - usually TCP and "sudo TCP" are enough.
# `sudo' is needed, as in some cases even root can get a "permission denied"
# on some file descriptors (case for heat_manager for example)
# UDP support is needed for octavia manager (UDP:5555).
lsof -n -w -P -a -iTCP:${ports} -p${pids} >&3 2>&1 || \
sudo -u $puser lsof -n -w -P -a -iTCP:${ports} -p${pids} >&3 2>&1 || \
lsof -w -P -a -iUDP:${ports} -p${pids} >&3 2>&1 || \
sudo -u $puser lsof -n -w -P -a -iUDP:${ports} -p${pids} >&3 2>&1
# First convert port to hex value. We need to 0-pad it in order to get the
# right format (4 chars).
for p in $@; do
ports="${ports}|$(printf '%0.4x' $p)"
done
# Format the string - will be ":(hex1|hex2|...)"
ports=":(${ports:1})"
# Parse the files. We need to extract only one value (socket inode) based on the matching port. Let's check local and target for establised connection.
# Line example:
# 534: DE0D10AC:1628 DE0D10AC:8B7C 01 00000000:00000000 02:000000D3 00000000 42439 0 574360 2 0000000000000000 20 4 0 10 -1
# | | |
# $2 local connection | $10 Socket inode
# $3 Connection target
# Using the main /proc/net/{tcp,udp} allow to take only the connections existing in the current container. If we were using /proc/PID/net/{tcp,udp}, we
# would get all the connections existing in the same network namespace as the PID. Since we're using network=host, that would show *everything*.
# the "join" method is weird, and fails if the array is empty.
# Note: join comes from gawk's /usr/share/awk/join.awk and has some weird parameters.
sockets=$(awk -i join -v m=${ports} '{IGNORECASE=1; if ($2 ~ m || $3 ~ m) {output[counter++] = $10} } END{if (length(output)>0) {print join(output, 0, length(output)-1, "|")}}' /proc/net/{tcp,udp})
# If no socket, just fail early
test -z $sockets && exit 1
match=0
for pid in $(pgrep -f $process); do
# Here, we check if a socket is actually associated to the process PIDs
match=$(( $match+$(sudo -u $puser find /proc/$pid/fd/ -ilname "socket*" -printf "%l\n" 2>/dev/null | grep -c -E "(${sockets})") ))
test $match -gt 0 && exit 0 # exit as soon as we get a match
done
exit 1 # no early exit, meaning failure.
}
healthcheck_listen () {


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