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fixes for race conditions and dupes in job queue

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we had situations where the manager would start workers on the same job,
either because of race conditions or because at the time of queueing it wasn't
known that the jobs were targeting the same device (due to device aliases).

this commit removes duplicate jobs, reduces the need for locking on the job
queue, and makes use of lldpRemChassisId to try to deduplicate jobs before
they are started. in effect we have several goes to prevent duplicate jobs:

1. at neighbor discovery time we try to skip queueing same lldpRemChassisId
2. at job selection we 'error out' jobs with same profile as job selected
3. at job selection we check for running job with same profile as selected
4. the job manager process also checks for duplicate job profiles
5. at job lock we abort if the job was 'errored out'

all together this seems to work well. a test on a large university network of
303 devices (four core routers and the rest edge routers, runing VRF with many
duplicate identities), ~1200 subnets, ~50k hosts, resulted in no DB deadlock
or contention and a complete discover+arpnip+macsuck (909 jobs) in ~3 minutes
(with ~150 duplicate jobs identified and skipped).
This commit is contained in:
Oliver Gorwits
2017-11-23 19:23:55 +00:00
parent 1bbe8c9164
commit 0bb15f36b9
10 changed files with 166 additions and 114 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
lib/App/Netdisco/Backend/Job.pm
View File

@@ -19,6 +19,7 @@ foreach my $slot (qw/
username
userip
log
device_key
_current_phase
_last_namespace

18
lib/App/Netdisco/Backend/Role/Manager.pm
View File

@@ -34,6 +34,16 @@ sub worker_begin {
}
}
# creates a 'signature' for each job so that we can check for duplicates ...
# it happens from time to time due to the distributed nature of the job queue
# and manager(s) - also kinder to the DB to skip here rather than jq_lock()
my $memoize = sub {
no warnings 'uninitialized';
my $job = shift;
return join chr(28), map {$job->{$_}}
(qw/action port subaction/, ($job->{device_key} ? 'device_key' : 'device'));
};
sub worker_body {
my $self = shift;
my $wid = $self->wid;
@@ -46,6 +56,7 @@ sub worker_body {
while (1) {
prctl sprintf 'nd2: #%s mgr: gathering', $wid;
my $num_slots = 0;
my %seen_job = ();
$num_slots = parse_max_workers( setting('workers')->{tasks} )
- $self->{queue}->pending();
@@ -54,6 +65,7 @@ sub worker_body {
# get some high priority jobs
# TODO also check for stale jobs in Netdisco DB
foreach my $job ( jq_getsomep($num_slots) ) {
next if $seen_job{ $memoize->($job) }++;
# mark job as running
next unless jq_lock($job);
@@ -71,6 +83,7 @@ sub worker_body {
# get some normal priority jobs
# TODO also check for stale jobs in Netdisco DB
foreach my $job ( jq_getsome($num_slots) ) {
next if $seen_job{ $memoize->($job) }++;
# mark job as running
next unless jq_lock($job);
@@ -81,6 +94,11 @@ sub worker_body {
$self->{queue}->enqueue($job);
}
#if (scalar grep {$_ > 1} values %seen_job) {
# debug 'WARNING: saw duplicate jobs after getsome()';
# use DDP; debug p %seen_job;
#}
debug "mgr ($wid): sleeping now...";
prctl sprintf 'nd2: #%s mgr: idle', $wid;
sleep( setting('workers')->{sleep_time} || 1 );

2
lib/App/Netdisco/DB.pm
View File

@@ -11,7 +11,7 @@ __PACKAGE__->load_namespaces(
);
our # try to hide from kwalitee
$VERSION = 44; # schema version used for upgrades, keep as integer
$VERSION = 45; # schema version used for upgrades, keep as integer
use Path::Class;
use File::ShareDir 'dist_dir';

2
lib/App/Netdisco/DB/Result/Admin.pm
View File

@@ -46,6 +46,8 @@ __PACKAGE__->add_columns(
{ data_type => "text", is_nullable => 1 },
"debug",
{ data_type => "boolean", is_nullable => 1 },
"device_key",
{ data_type => "text", is_nullable => 1 },
);

5
lib/App/Netdisco/DB/Result/Device.pm
View File

@@ -238,6 +238,7 @@ sub renumber {
if $new_ip eq '0.0.0.0'
or $new_ip eq '127.0.0.1';
# Community is not included as SNMP::test_connection will take care of it
foreach my $set (qw/
DeviceIp
DeviceModule
@@ -259,10 +260,6 @@ sub renumber {
->search({remote_ip => $old_ip})
->update({remote_ip => $new_ip});
$schema->resultset('Admin')
->search({device => $old_ip})
->update({device => $new_ip});
$schema->resultset('Node')
->search({switch => $old_ip})
->update({switch => $new_ip});

228
lib/App/Netdisco/JobQueue/PostgreSQL.pm
View File

@@ -13,11 +13,11 @@ use Try::Tiny;
use base 'Exporter';
our @EXPORT = ();
our @EXPORT_OK = qw/
jq_warm_thrusters
jq_getsome
jq_getsomep
jq_locked
jq_queued
jq_warm_thrusters
jq_lock
jq_defer
jq_complete
@@ -28,67 +28,6 @@ our @EXPORT_OK = qw/
/;
our %EXPORT_TAGS = ( all => \@EXPORT_OK );
sub _getsome {
my ($num_slots, $where) = @_;
return () if ((!defined $num_slots) or ($num_slots < 1));
return () if ((!defined $where) or (ref {} ne ref $where));
my $jobs = schema('netdisco')->resultset('Admin');
my $rs = $jobs->search({
status => 'queued',
device => { '-not_in' =>
$jobs->skipped(setting('workers')->{'BACKEND'},
setting('workers')->{'max_deferrals'},
setting('workers')->{'retry_after'})
->columns('device')->as_query },
%$where,
}, { order_by => 'random()', rows => $num_slots });
my @returned = ();
while (my $job = $rs->next) {
push @returned, App::Netdisco::Backend::Job->new({ $job->get_columns });
}
return @returned;
}
sub jq_getsome {
return _getsome(shift,
{ action => { -in => setting('job_prio')->{'normal'} } }
);
}
sub jq_getsomep {
return _getsome(shift, {
-or => [{
username => { '!=' => undef },
action => { -in => setting('job_prio')->{'normal'} },
},{
action => { -in => setting('job_prio')->{'high'} },
}],
});
}
sub jq_locked {
my @returned = ();
my $rs = schema('netdisco')->resultset('Admin')
->search({ status => ('queued-'. setting('workers')->{'BACKEND'}) });
while (my $job = $rs->next) {
push @returned, App::Netdisco::Backend::Job->new({ $job->get_columns });
}
return @returned;
}
sub jq_queued {
my $job_type = shift;
return schema('netdisco')->resultset('Admin')->search({
device => { '!=' => undef},
action => $job_type,
status => { -like => 'queued%' },
})->get_column('device')->all;
}
# given a device, tests if any of the primary acls applies
# returns a list of job actions to be denied/skipped on this host.
sub _get_denied_actions {
@@ -130,49 +69,126 @@ sub jq_warm_thrusters {
});
}
sub _getsome {
my ($num_slots, $where) = @_;
return () if ((!defined $num_slots) or ($num_slots < 1));
return () if ((!defined $where) or (ref {} ne ref $where));
my $jobs = schema('netdisco')->resultset('Admin');
my $rs = $jobs->search({
status => 'queued',
device => { '-not_in' =>
$jobs->skipped(setting('workers')->{'BACKEND'},
setting('workers')->{'max_deferrals'},
setting('workers')->{'retry_after'})
->columns('device')->as_query },
%$where,
}, { order_by => 'random()', rows => $num_slots });
my @returned = ();
while (my $job = $rs->next) {
if ($job->device) {
# need to handle device discovered since backend daemon started
# and the skiplist was primed. these should be checked against
# the various acls and have device_skip entry added if needed,
# and return false if it should have been skipped.
my @badactions = _get_denied_actions($job->device);
if (scalar @badactions) {
schema('netdisco')->resultset('DeviceSkip')->find_or_create({
backend => setting('workers')->{'BACKEND'}, device => $job->device,
},{ key => 'device_skip_pkey' })->add_to_actionset(@badactions);
# will now not be selected in a future _getsome()
next if scalar grep {$_ eq $job->action} @badactions;
}
}
# remove any duplicate jobs, incuding possibly this job if there
# is already an equivalent job running
my %job_properties = (
action => $job->action,
port => $job->port,
subaction => $job->subaction,
-or => [
{ device => $job->device },
($job->device_key ? ({ device_key => $job->device_key }) : ()),
],
);
my $gone = $jobs->search({
status => 'queued',
-and => [
%job_properties,
-or => [{
job => { '!=' => $job->id },
},{
job => $job->id,
-exists => $jobs->search({
status => { -like => 'queued-%' },
%job_properties,
})->as_query,
}],
],
}, {for => 'update'})
->update({ status => 'error', log => (sprintf 'duplicate of %s', $job->id) });
debug sprintf 'getsome: cancelled %s duplicate(s) of job %s', ($gone || 0), $job->id;
push @returned, App::Netdisco::Backend::Job->new({ $job->get_columns });
}
return @returned;
}
sub jq_getsome {
return _getsome(shift,
{ action => { -in => setting('job_prio')->{'normal'} } }
);
}
sub jq_getsomep {
return _getsome(shift, {
-or => [{
username => { '!=' => undef },
action => { -in => setting('job_prio')->{'normal'} },
},{
action => { -in => setting('job_prio')->{'high'} },
}],
});
}
sub jq_locked {
my @returned = ();
my $rs = schema('netdisco')->resultset('Admin')
->search({ status => ('queued-'. setting('workers')->{'BACKEND'}) });
while (my $job = $rs->next) {
push @returned, App::Netdisco::Backend::Job->new({ $job->get_columns });
}
return @returned;
}
sub jq_queued {
my $job_type = shift;
return schema('netdisco')->resultset('Admin')->search({
device => { '!=' => undef},
action => $job_type,
status => { -like => 'queued%' },
})->get_column('device')->all;
}
sub jq_lock {
my $job = shift;
my $happy = false;
if ($job->device) {
# need to handle device discovered since backend daemon started
# and the skiplist was primed. these should be checked against
# the various acls and have device_skip entry added if needed,
# and return false if it should have been skipped.
my @badactions = _get_denied_actions($job->device);
if (scalar @badactions) {
schema('netdisco')->resultset('DeviceSkip')->find_or_create({
backend => setting('workers')->{'BACKEND'}, device => $job->device,
},{ key => 'device_skip_pkey' })->add_to_actionset(@badactions);
return false if scalar grep {$_ eq $job->action} @badactions;
}
}
# lock db row and update to show job has been picked
try {
schema('netdisco')->txn_do(sub {
schema('netdisco')->resultset('Admin')
->search({ job => $job->id }, { for => 'update' })
->update({ status => ('queued-'. setting('workers')->{'BACKEND'}) });
my $updated = schema('netdisco')->resultset('Admin')
->search({ job => $job->id, status => 'queued' }, { for => 'update' })
->update({ status => ('queued-'. setting('workers')->{'BACKEND'}) });
return unless
schema('netdisco')->resultset('Admin')
->count({ job => $job->id,
status => ('queued-'. setting('workers')->{'BACKEND'}) });
# remove any duplicate jobs, needed because we have race conditions
# when queueing jobs of a type for all devices
schema('netdisco')->resultset('Admin')->search({
status => 'queued',
device => $job->device,
port => $job->port,
action => $job->action,
subaction => $job->subaction,
}, {for => 'update'})->delete();
$happy = true;
});
$happy = true if $updated > 0;
}
catch {
error $_;
@@ -243,6 +259,7 @@ sub jq_complete {
$happy = true;
}
catch {
# use DDP; p $job;
error $_;
};
@@ -274,13 +291,14 @@ sub jq_insert {
schema('netdisco')->txn_do(sub {
schema('netdisco')->resultset('Admin')->populate([
map {{
device => $_->{device},
port => $_->{port},
action => $_->{action},
subaction => ($_->{extra} || $_->{subaction}),
username => $_->{username},
userip => $_->{userip},
status => 'queued',
device => $_->{device},
device_key => $_->{device_key},
port => $_->{port},
action => $_->{action},
subaction => ($_->{extra} || $_->{subaction}),
username => $_->{username},
userip => $_->{userip},
status => 'queued',
}} @$jobs
]);
});

4
lib/App/Netdisco/Worker/Plugin/Discover/CanonicalIP.pm
View File

@@ -72,6 +72,10 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
$device->renumber($new_ip)
or die "cannot renumber to: $new_ip"; # rollback
# is not done in renumber but required otherwise confusing at job end!
schema('netdisco')->resultset('Admin')
->find({job => $job->id})->update({device => $new_ip});
return Status->noop(sprintf ' [%s] device - changed IP to %s (%s)',
$old_ip, $device->ip, ($device->dns || ''));
});

12
lib/App/Netdisco/Worker/Plugin/Discover/Neighbors.pm
View File

@@ -39,11 +39,13 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
or return Status->defer("discover failed: could not SNMP connect to $device");
my @to_discover = store_neighbors($device);
my %seen_id = ();
# only enqueue if device is not already discovered,
# discover_* config permits the discovery
foreach my $neighbor (@to_discover) {
my ($ip, $remote_type) = @$neighbor;
my ($ip, $remote_type, $remote_id) = @$neighbor;
next if $remote_id and $seen_id{ $remote_id }++;
my $device = get_device($ip);
next if $device->in_storage;
@@ -55,10 +57,14 @@ register_worker({ phase => 'main', driver => 'snmp' }, sub {
next;
}
# risk of things going wrong...?
# https://quickview.cloudapps.cisco.com/quickview/bug/CSCur12254
jq_insert({
device => $ip,
action => 'discover',
subaction => 'with-nodes',
($remote_id ? (device_key => $remote_id) : ()),
});
}
});
@@ -171,7 +177,7 @@ sub store_neighbors {
# useable remote IP...
if ($remote_ip eq '0.0.0.0' or
check_acl_no($remote_ip, 'group:__LOCAL_ADDRESSES__')) {
check_acl_no($remote_ip, 'group:__LOCAL_ADDRESSES__')) {
if ($remote_id) {
my $devices = schema('netdisco')->resultset('Device');
@@ -228,7 +234,7 @@ sub store_neighbors {
debug sprintf
' [%s] neigh - adding neighbor %s, type [%s], on %s to discovery queue',
$device->ip, $remote_ip, ($remote_type || ''), $port;
push @to_discover, [$remote_ip, $remote_type];
push @to_discover, [$remote_ip, $remote_type, $remote_id];
$remote_port = $c_port->{$entry};
if (defined $remote_port) {

3
lib/App/Netdisco/Worker/Plugin/Expire.pm
View File

@@ -6,6 +6,7 @@ use aliased 'App::Netdisco::Worker::Status';
use Dancer::Plugin::DBIC 'schema';
use App::Netdisco::Util::Statistics 'update_stats';
use App::Netdisco::DB::ExplicitLocking ':modes';
register_worker({ phase => 'main' }, sub {
my ($job, $workerconf) = @_;
@@ -40,7 +41,7 @@ register_worker({ phase => 'main' }, sub {
}
if (setting('expire_jobs') and setting('expire_jobs') > 0) {
schema('netdisco')->txn_do(sub {
schema('netdisco')->txn_do_locked('admin', 'EXCLUSIVE', sub {
schema('netdisco')->resultset('Admin')->search({
entered => \[q/< (now() - ?::interval)/,
(setting('expire_jobs') * 86400)],

5
share/schema_versions/App-Netdisco-DB-44-45-PostgreSQL.sql Normal file
View File

@@ -0,0 +1,5 @@
BEGIN;
ALTER TABLE "admin" ADD "device_key" text;
COMMIT;