nixos/estuary: Implement 95% bandwidth limiter

This commit is contained in:
Jack O'Sullivan 2022-07-10 23:27:57 +01:00
parent e240b9a54e
commit 408177adb3
3 changed files with 182 additions and 56 deletions

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@ -0,0 +1,93 @@
{ lib, pkgs, config, assignments, allAssignments, ... }: {
config = {
systemd = {
services = {
# systemd-networkd doesn't support tc filtering
wan-filter-to-ifb =
let
waitOnline = [
"systemd-networkd-wait-online@wan.service"
"systemd-networkd-wait-online@ifb-wan.service"
];
in
{
description = "Install tc filter to pass WAN traffic to IFB";
enable = true;
bindsTo = waitOnline;
after = waitOnline;
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
};
script = ''
${pkgs.iproute2}/bin/tc filter add dev wan parent ffff: u32 match u32 0 0 action mirred egress redirect dev ifb-wan
'';
wantedBy = [ "multi-user.target" ];
};
bandwidth-limiter =
let
deps = [ "wan-filter-to-ifb.service" ];
in
{
description = "WAN bandwidth limiter";
enable = true;
bindsTo = deps;
after = deps;
path = with pkgs; [ python310 iproute2 ];
environment = {
PYTHONUNBUFFERED = "1";
};
serviceConfig = {
ExecStart = [ "${./bandwidth.py} wan,ifb-wan 245 10000" ];
StateDirectory = "bandwidth-limiter";
};
wantedBy = [ "multi-user.target" ];
};
};
network = {
netdevs = {
"25-ifb-wan".netdevConfig = {
Name = "ifb-wan";
Kind = "ifb";
};
};
networks = {
"80-wan" = {
extraConfig = ''
[QDisc]
Parent=ingress
Handle=ffff
# Outbound traffic limiting
[TokenBucketFilter]
Parent=root
LatencySec=0.3
BurstBytes=512K
# *bits
Rate=245M
'';
};
"80-ifb-wan" = {
matchConfig.Name = "ifb-wan";
extraConfig = ''
# Inbound traffic limiting
[TokenBucketFilter]
Parent=root
LatencySec=0.3
BurstBytes=512K
# *bits
Rate=245M
'';
};
};
};
};
my = {
tmproot.persistence.config.directories = [ "/var/lib/bandwidth-limiter" ];
};
};
}

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@ -0,0 +1,88 @@
#!/usr/bin/env python
import time
import datetime
import sys
import os
import subprocess
import json
import signal
import shlex
INTERVAL = 5 * 60
HZ = 1000
LATENCY = '300ms'
def end_of_month(dt: datetime.datetime):
return datetime.datetime(dt.year, dt.month + 1 if dt.month != 12 else 1, 1) - datetime.timedelta(seconds=1)
def start_of_month(dt: datetime.datetime):
return datetime.datetime(dt.year, dt.month, 1)
def month_seconds(dt: datetime.datetime):
return (end_of_month(dt) - start_of_month(dt)).total_seconds()
def month_fraction(dt: datetime.datetime):
return (dt - start_of_month(dt)).total_seconds() / month_seconds(dt)
def main():
if len(sys.argv) != 4:
print(f'usage: {sys.argv[0]} <interfaces> <95% limit mbit> <hi limit mbit>')
sys.exit(1)
ifaces = sys.argv[1].split(',')
lo = int(sys.argv[2])
hi = int(sys.argv[3])
cutoff = int((lo / 8) * 1024 * 1024 * INTERVAL)
basedir = os.environ['STATE_DIRECTORY']
def sig_handler(signum, frame):
sys.exit(0)
signal.signal(signal.SIGTERM, sig_handler)
last_total = 0
while True:
now = datetime.datetime.now()
total = 0
for n in ifaces:
output = subprocess.check_output(['ip', '-j', '-s', 'link', 'show', 'dev', n], encoding='utf-8')
stats = json.loads(output)
total += stats[0]['stats64']['tx']['bytes']
if last_total == 0:
last_total = total
data_file = os.path.join(basedir, str(now.year), f'{now.month}.json')
os.makedirs(os.path.dirname(data_file), exist_ok=True)
data = {
'hi_fraction_used': 0.0,
}
if os.path.exists(data_file):
with open(data_file, 'r') as f:
data = json.load(f)
if total - last_total > cutoff:
print(f'used more than {lo}mbps over the last {INTERVAL}s')
data['hi_fraction_used'] += INTERVAL / month_seconds(now)
limit = hi
mf = month_fraction(now)
if data['hi_fraction_used'] >= mf:
print(f"warning: used too many 5% buckets so far {data['hi_fraction_used']} and we are {mf} into the month); applying bandwidth limit")
limit = lo
with open(data_file, 'w') as f:
json.dump(data, f)
qdisc_args = ['rate', f'{limit}mbit', 'burst', str(int(((limit*1000*1000)/HZ/8) * 4)), 'latency', LATENCY]
for n in ifaces:
subprocess.check_call(['tc', 'qdisc', 'change', 'dev', n, 'root', 'tbf'] + qdisc_args)
last_total = total
time.sleep(INTERVAL)
if __name__ == '__main__':
main()

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@ -39,7 +39,7 @@
inherit (lib.my) networkdAssignment;
in
{
imports = [ "${modulesPath}/profiles/qemu-guest.nix" ./dns.nix ];
imports = [ "${modulesPath}/profiles/qemu-guest.nix" ./dns.nix ./bandwidth.nix ];
config = mkMerge [
{
@ -92,29 +92,6 @@
'';
wantedBy = [ "multi-user.target" ];
};
# systemd-networkd doesn't support tc filtering
wan-filter-to-ifb =
let
waitOnline = [
"systemd-networkd-wait-online@wan.service"
"systemd-networkd-wait-online@ifb-wan.service"
];
in
{
description = "Install tc filter to pass WAN traffic to IFB";
enable = true;
bindsTo = waitOnline;
after = waitOnline;
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
};
script = ''
${pkgs.iproute2}/bin/tc filter add dev wan parent ffff: u32 match u32 0 0 action mirred egress redirect dev ifb-wan
'';
wantedBy = [ "multi-user.target" ];
};
};
};
@ -135,13 +112,6 @@
};
};
netdevs = {
"25-ifb-wan".netdevConfig = {
Name = "ifb-wan";
Kind = "ifb";
};
};
networks = {
"80-wan" = {
matchConfig.Name = "wan";
@ -160,31 +130,6 @@
LinkLocalAddressing = "no";
IPv6AcceptRA = false;
};
extraConfig = ''
[QDisc]
Parent=ingress
Handle=ffff
# Outbound traffic limiting
[TokenBucketFilter]
Parent=root
LatencySec=0.3
BurstBytes=512K
# *bits
Rate=245M
'';
};
"80-ifb-wan" = {
matchConfig.Name = "ifb-wan";
extraConfig = ''
# Inbound traffic limiting
[TokenBucketFilter]
Parent=root
LatencySec=0.3
BurstBytes=512K
# *bits
Rate=245M
'';
};
"80-base" = mkMerge [