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AWS Transit Gateway

Overview​

AWS Transit Gateway connects VPCs and on-premises networks through a central hub. This simplifies your network and puts an end to complex peering relationships. It acts as a cloud router – each new connection is only made once.

Because of its central position, AWS Transit Gateway Network Manager has a unique view over your entire network, even connecting to Software-Defined Wide Area Network (SD-WAN) devices.

The AWS Transit Gateway Centreon Monitoring Connector uses the Amazon Cloudwatch APIs to collect the related metrics and status.

Monitoring Connector assets​

Monitored objects​

  • AWS Transit Gateways

Discovery rules​

Rule nameDescription
Cloud-Aws-Transitgateways-GatewaysDiscover the Transit Gateways within an AWS infrastructure

Collected metrics​

More information about collected metrics is available in the official Amazon documentation: https://docs.aws.amazon.com/fr_fr/vpc/latest/tgw/transit-gateway-cloudwatch-metrics

Metric nameDescriptionUnit
gateway.traffic.in.bytesThe number of bytes received by the transit gateway.B
gateway.traffic.out.bytesThe number of bytes sent from the transit gateway.B
gateway.packets.in.countThe number of packets received by the transit gateway.
gateway.packets.out.countThe number of packets sent by the transit gateway.
gateway.packets.blackholedropped.countThe number of packets dropped because they matched a blackhole route.
gateway.packets.noroutedropped.countThe number of packets dropped because they did not match a route.

All these metrics can be calculated on a per-second time reference rather than displaying the absolute value. To do so, simply add the setting --per-sec to the command and/or the Service Macros

By default, the Gateways-Traffic-Global Service will monitor all of the Transit Gateways of the AWS infrastructure. To get one Service per Gateway, use the Service Autodiscovery module with the rule described above.

Prerequisites​

AWS Configuration​

Configure a service account (access/secret keys combo) for which the following privileges have to be granted:

AWS PrivilegeDescription
cloudwatch:getMetricStatisticsGet metrics values from Cloudwatch AWS/TransitGateway namespace

Plugin dependencies​

To interact with Amazon APIs, you can use either use the awscli binary provided by Amazon or paws, a Perl AWS SDK (recommended). You must install it on every Centreon poller expected to monitor AWS resources: 

yum install perl-Paws

For now, it is not possible to use paws if you are using a proxy to reach AWS Cloudwatch APIs.

Setup​

  1. Install the Centreon package on every Centreon poller expected to monitor AWS Transit Gateway resources:
yum install centreon-plugin-Cloud-Aws-Transitgateway-Api
  1. On the Centreon Web interface, install the AWS Transit Gateway Centreon Monitoring Connector on the Configuration > Monitoring Connectors Manager page

Configuration​

Host​

  • Log into Centreon and add a new Host through "Configuration > Hosts".
  • In the IP Address/FQDN field, set the following IP address: '127.0.0.1'
  • Select the Cloud-Aws-Transitgateway-custom template to apply to the Host.
  • Once the template applied, some Macros marked as 'Mandatory' hereafter have to be configured:
MandatoryNomDescription
XAWSSECRETKEYAWS Secret key of your IAM role. Password checkbox must be checked
XAWSACESSKEYAWS Access key of your IAM role. Password checkbox must be checked
XAWSREGIONRegion where the instance is running
XAWSCUSTOMMODECustom mode to get metrics, 'awscli' is the default, you can also use 'paws' perl library
PROXYURLConfigure proxy URL
EXTRAOPTIONSAny extra option you may want to add to every command_line (eg. a --verbose flag)
DUMMYSTATUSHost state. Default is OK, do not modify it unless you know what you are doing
DUMMYOUTPUTHost check output. Default is 'This is a dummy check'. Customize it with your own if needed

FAQ​

How to check in the CLI that the configuration is OK and what are the main options for ?​

Once the Plugin installed, log into your Centreon Poller CLI using the centreon-engine user account and test the Plugin by running the following command (Some of the parameters such as --proxyurl have to be adjusted):

/usr/lib/centreon/plugins/centreon_aws_transitgateway_api.pl \
    --plugin=cloud::aws::transitgateway::plugin \
    --mode=traffic \
    --custommode=awscli \
    --aws-secret-key='*******************' \
    --aws-access-key='**********' \
    --region='eu-west-1' \
    --proxyurl='http://myproxy.mycompany.org:8080' \
    --timeframe='600' \
    --period='60' \
    --filter-gateway='tgw-01234567890abcd' \
    --warning-packets-drop-blackhole='500' \
    --critical-packets-drop-blackhole='1000' \
    --verbose

Expected command output is shown below: 

OK: 'tgw-01234567890abcd' Statistic 'Average' Metrics Bytes In: 2.89 MB, Bytes Out: 2.78 MB, Packets Received (In): 3844.04 ,
Packets Drop Blackhole: 0.00 , Packets Sent (Out): 3677.79 , Packets Drop No Route: 0.01  |
'tgw-01234567890abcd~average#gateway.traffic.in.bytes'=3026151.39B;;;; 'tgw-01234567890abcd~average#gateway.traffic.out.bytes'=2920220.01B;;;;
'tgw-01234567890abcd~average#gateway.packets.in.count'=3844.04;;;; 'tgw-01234567890abcd~average#gateway.packets.blackholedropped.count'=0.00;;;;
'tgw-01234567890abcd~average#gateway.packets.out.count'=3677.79;;;; 'tgw-01234567890abcd~average#gateway.packets.noroutedropped.count'=0.01;;;;

The command above monitors the traffic statistics of the Transit Gateway service (--plugin=cloud::aws::transitgateway::plugin --mode=traffic) within an AWS infrastructure. AWS account credentials are used to authenticate against and to connect to the API (--aws-secret-key='****' --aws-access-key='****'). The calculated metrics are an average of values on a 600 secondes / 10 min period (--timeframe='600') with one sample per 60s / 1 minute (--period='60').

This command would trigger a 'WARNING' alert if the number of the packets dropped by a blackhole rule during the sample period is over 500 (--warning-packets-drop-blackhole='500'). The alert would be 'CRITICAL' over 1000 dropped packets (--critical-packets-drop-blackhole='1000').

All the available thresholds parameters can be displayed by adding the
--help parameter to the command:

/usr/lib/centreon/plugins/centreon_aws_transitgateway_api.pl \
    --plugin=cloud::aws::transitgateway::plugin \
    --mode=traffic \
    --help

Why do I get the following result:​

UNKNOWN: No metrics. Check your options or use --zeroed option to set 0 on undefined values ?​

This command result means that Amazon Cloudwatch does not have any value for the requested period.

This result can be overriden by adding the --zeroed option in the command. This will force a value of 0 when no metric has been collected and will prevent the UNKNOWN error message.

UNKNOWN: Command error: - An error occurred (AuthFailure) [...] ?​

This command result means that the credentials provided don't have enough privileges to perform the underlying AWS Operation.

UNKNOWN: 500 Can't connect to monitoring.eu-west-1.amazonaws.com:443 |​

This error message means that the Centreon Plugin couldn't successfully connect to the AWS Cloudwatch API. Check that no third party device (such as a firewall) is blocking the request. A proxy connection may also be necessary to connect to the API. This can be done by using this option in the command: --proxyurl='http://proxy.mycompany:8080'.