Tutorial / Cram Notes

Amazon CloudWatch Metrics

Amazon CloudWatch is a monitoring service that provides visibility into AWS resources and applications. For networking, CloudWatch offers several important metrics.

VPC Flow Logs

VPC Flow Logs record data about the IP traffic going to and from the network interfaces in your Virtual Private Cloud (VPC). Flow logs can be created at three levels: the VPC, the subnet, or the network interface.

Examples include:

  • The number of accepted and rejected packets.
  • The source IP address and the destination IP address.
  • The source and destination ports.

CloudWatch NetworkELB Metrics

For Elastic Load Balancing, network Load Balancer (NetworkELB) metrics provide information about TCP traffic on your network load balancer.

Key metrics include:

  • ActiveFlowCount: The number of flow creations initiated by your AWS resource.
  • ProcessedBytes: The total number of bytes processed by the load balancer.

AWS Transit Gateway Metrics

AWS Transit Gateway connects VPCs and on-premises networks. Monitoring Transit Gateway is necessary to determine the health and performance of interconnectivity between networks.

Important metrics are:

  • BytesIn, BytesOut: The volume of bytes transferred in and out of the transit gateway.
  • PacketDropCountBlackhole: The number of packets dropped because they matched a route to a black hole.

AWS Direct Connect Metrics

AWS Direct Connect provides private connectivity between AWS and your data center. Monitoring it can ensure the network performs optimally.

Metrics to observe:

  • ConnectionState: Indicates the state of the connection (i.e., available, down, deleting, etc.).
  • DataOut, DataIn: The data transferred out of and into AWS over your Direct Connect connection.

AWS VPN Metrics

AWS VPN enables you to establish a secure and private tunnel from your network or device to the AWS global network.

Examples of VPN metrics include:

  • TunnelState: Tracks the status of VPN tunnels (e.g., UP or DOWN).
  • TunnelDataIn, TunnelDataOut: The volume of data going into and out of each VPN tunnel.

Recommendations for Effective Monitoring

To effectively monitor the network status in AWS, it’s not enough to just collect metrics; you have to choose the right ones to focus on and know how to interpret them.

Combining Metrics for Better Insight

You can combine metrics to gauge network health better. For example, high ProcessedBytes in NetworkELB with little to no increase in ActiveFlowCount might indicate large file transfers without a corresponding increase in client connections.

Setting Alarms and Notifications

Set CloudWatch alarms to notify you when metrics surpass defined thresholds. For instance, you could set an alarm for when PacketDropCountBlackhole exceeds a certain number per minute, indicating a potential misconfiguration in your route tables.

Integration with Other AWS Services

For a comprehensive view, integrate CloudWatch with other AWS services such as Amazon CloudTrail for auditing API calls, and AWS Config for monitoring resource configurations.

Visualization

Visualizing the data can simplify understanding complex network behaviors and patterns. AWS CloudWatch Dashboards can be used to create visual representations of your metrics, allowing for real-time monitoring of network status.

AWS CloudWatch Dashboard Example

Here’s an example of a simple dashboard widget for tracking ActiveFlowCount metrics of a NetworkELB:

{
“widgets”: [
{
“type”: “metric”,
“x”: 0,
“y”: 0,
“width”: 12,
“height”: 6,
“properties”: {
“metrics”: [
[ “AWS/NetworkELB”, “ActiveFlowCount”, “LoadBalancer”, “example-load-balancer-name” ]
],
“period”: 300,
“stat”: “Average”,
“region”: “us-west-1”,
“title”: “Active Flow Count for example-load-balancer-name”
}
}
]
}

Conclusion

Monitoring the network in AWS environments requires a nuanced approach that goes beyond what a traditional on-premises network might entail. By leveraging the AWS-specific metrics such as those from CloudWatch, Transit Gateway, Direct Connect, and VPN, you can gain in-depth visibility into your network’s performance and health. Implementing proactive monitoring strategies like combining metrics, setting thresholds for alarms, and creating visual dashboards will enable you to maintain a high standard of networking for applications and services in AWS.

Practice Test with Explanation

True or False: Network Packet Loss is an unnecessary metric for visibility and should not be monitored in AWS.

  • (A) True
  • (B) False

Answer: B

Explanation: Network Packet Loss is an important metric to monitor as it can indicate problems in network performance and potentially impact application reliability and user experience.

Which AWS service provides detailed insights into the traffic that flows through your AWS environment?

  • (A) AWS X-Ray
  • (B) AWS CloudWatch
  • (C) AWS VPC Flow Logs
  • (D) AWS Direct Connect

Answer: C

Explanation: AWS VPC Flow Logs capture information about the IP traffic going to and from network interfaces in your VPC, giving detailed insights into the traffic flow.

What metric would you use to monitor the status of VPN tunnels in AWS?

  • (A) StatusCheckFailed
  • (B) TunnelState
  • (C) NetworkPacketsIn
  • (D) NetworkPacketsOut

Answer: B

Explanation: The TunnelState metric in AWS CloudWatch allows you to monitor the status of your AWS Site-to-Site VPN tunnels.

Which of the following is NOT a recommended metric to monitor for AWS Direct Connect?

  • (A) ConnectionState
  • (B) VirtualInterfaceState
  • (C) CPU Utilization
  • (D) PbpsEgress

Answer: C

Explanation: CPU Utilization is not a metric associated with AWS Direct Connect; it’s more relevant for Amazon EC2 instances. ConnectionState and VirtualInterfaceState are relevant Direct Connect metrics.

True or False: The “NetworkIn” and “NetworkOut” metrics in Amazon EC2 are useful for determining the throughput of a particular instance.

  • (A) True
  • (B) False

Answer: A

Explanation: The “NetworkIn” and “NetworkOut” metrics for EC2 instances represent the inbound and outbound network traffic and are useful for monitoring the throughput of the instance.

What AWS CloudWatch metric would be most useful for identifying network bandwidth issues?

  • (A) CPUUtilization
  • (B) DiskReadOps
  • (C) NetworkPacketsIn
  • (D) NetworkIn/NetworkOut

Answer: D

Explanation: The NetworkIn and NetworkOut metrics record the volume of incoming and outgoing traffic for an instance, which can be indicative of bandwidth issues.

What AWS service combined with CloudWatch would you use to be alerted about high latency in your network?

  • (A) AWS CloudTrail
  • (B) AWS Config
  • (C) AWS Lambda
  • (D) Amazon CloudWatch Alarms

Answer: D

Explanation: Amazon CloudWatch Alarms can be configured to notify you if certain thresholds for network latency or other performance metrics are breached.

True or False: AWS CloudWatch supports custom metrics generated from your application.

  • (A) True
  • (B) False

Answer: A

Explanation: AWS CloudWatch allows you to publish your own metrics directly to Amazon CloudWatch and then view them alongside the default system metrics.

Which feature can be used to measure the round trip time (RTT) for traffic going between your VPC and a user’s location?

  • (A) AWS Route 53 Health Checks
  • (B) AWS CloudWatch NetworkInsightsPath
  • (C) AWS CloudTrail Activity Monitoring
  • (D) Amazon VPC Flow Logs

Answer: B

Explanation: AWS CloudWatch NetworkInsightsPath allows you to analyze network paths, which can include measuring the round trip time (RTT) for traffic communication.

When monitoring an AWS Transit Gateway, which metric indicates the number of bytes sent out by the Transit Gateway to the attachment over a specified period of time?

  • (A) BytesIn
  • (B) BytesOut
  • (C) PacketsIn
  • (D) PacketsOut

Answer: B

Explanation: The BytesOut metric would be used to monitor the number of bytes that are sent out by the AWS Transit Gateway to the attachment.

True or False: “HTTPCode_ELB_5XX_Count” is an Amazon CloudWatch metric directly related to network status visibility.

  • (A) True
  • (B) False

Answer: B

Explanation: “HTTPCode_ELB_5XX_Count” tracks the number of HTTP 5XX server error codes that an Elastic Load Balancer returns, which is more indicative of application-level issues rather than network status.

Which CloudWatch metric should be monitored to investigate network connectivity issues to an EC2 instance?

  • (A) StatusCheckFailed_Instance
  • (B) StatusCheckFailed_System
  • (C) NetworkPacketsIn
  • (D) All of the above

Answer: D

Explanation: StatusCheckFailed_Instance and StatusCheckFailed_System refer to statuses reported by the instance and, along with NetworkPacketsIn metrics, can help identify connectivity issues to an EC2 instance.

Interview Questions

What key metrics would you recommend monitoring to assess the health of a VPC network on AWS?

Key metrics to monitor in a VPC include network throughput, packet loss, latency, and error rates. On AWS, you can use Amazon CloudWatch to monitor these metrics for your Elastic Network Interfaces (ENIs). Throughput can be tracked by monitoring the ‘NetworkIn’ and ‘NetworkOut’ metrics, which measure the inbound and outbound traffic. Latency can be inferred from round-trip time measurements if available. Packet loss is not directly reported by AWS CloudWatch but can be deduced from retransmission metrics or custom metrics sent from within the instances themselves.

How can Amazon CloudWatch Logs help in providing visibility of the network status?

Amazon CloudWatch Logs can be used to collect and monitor log files from your EC2 instances and other AWS resources. For network visibility, VPC Flow Logs can be enabled and stored in CloudWatch Logs. These logs provide data about the IP traffic going to and from network interfaces in your VPC, helping to diagnose overly restrictive security group rules, network ACLs, and understand traffic patterns.

When designing a multi-region application, which metrics are critical to ensure network responsiveness and reliability?

For multi-region applications, it is important to monitor latency, cross-region traffic, error rates, and region-specific metrics like API call errors and latency for each AWS service being used. Using CloudWatch, you can collect these metrics and analyze them to ensure that network performance between regions is optimal and to troubleshoot any regional discrepancies.

Can you describe the significance of monitoring the ‘BurstBalance’ metric for an AWS Network File System (NFS)?

The ‘BurstBalance’ metric is crucial for monitoring with Amazon Elastic File System (EFS) as it indicates the available burst credits of a file system that allow throughput to exceed the baseline level. When ‘BurstBalance’ is high, you have a high credit balance and can burst throughput to a higher level when needed. Monitoring this metric ensures that your file system can handle workload spikes without degrading performance.

In the context of AWS Direct Connect, why is it important to monitor the ‘ConnectionState’ and ‘VirtualInterfaceState’ metrics?

Monitoring ‘ConnectionState’ and ‘VirtualInterfaceState’ are both critical to ensuring that your AWS Direct Connect connections are functioning as expected. ‘ConnectionState’ indicates whether a connection is available, down, or in an intermediate state, while ‘VirtualInterfaceState’ shows the state of virtual interfaces which are responsible for carrying network traffic. Monitoring these metrics helps detect and troubleshoot connectivity issues, which is vital for maintaining a stable and reliable direct connection to AWS services.

What CloudWatch metric should you pay attention to for quickly identifying potential issues with an elastic load balancer’s (ELB) performance?

Important CloudWatch metrics for an ELB include ‘HealthyHostCount’, ‘UnHealthyHostCount’, ‘RequestCount’, ‘HTTPCode_Backend_5XX’, and ‘Latency’. An anomalously low ‘HealthyHostCount’ or high ‘UnHealthyHostCount’ can signal issues with backend instances. An increase in ‘HTTPCode_Backend_5XX’ errors or high ‘Latency’ can also point towards performance concerns that might need immediate attention.

How does Amazon CloudWatch’s ‘Percentiles’ statistics feature assist in network performance monitoring?

‘Percentiles’ in CloudWatch allow you to capture and understand the distribution of metric data, which can be more insightful than average metrics when analyzing network performance. For example, high percentiles (like the 95th or 99th) of latency can reveal occasional spikes that might not affect the average but can significantly degrade user experiences. Tracking these can help you tune performance and make sure that the majority of requests meet your targeted response times.

For continuous network traffic analysis in AWS, how might you utilize Amazon VPC Flow Logs in conjunction with network monitoring tools?

Amazon VPC Flow Logs capture detailed information on the IP traffic in a VPC and can be published to Amazon CloudWatch Logs or Amazon S To provide continuous, detailed network traffic analysis, the data from VPC Flow Logs can be integrated with network monitoring tools (like third-party SIEM or AWS-native services such as Amazon Athena for queries on S3, or Amazon Kinesis for real-time processing) to perform pattern analysis, detect anomalies, and troubleshoot network issues.

When monitoring VPN connections in AWS, which metric would alert you to a potential problem with the amount of data being transmitted over your VPN tunnel?

In AWS, the ‘TunnelDataIn’ and ‘TunnelDataOut’ CloudWatch metrics for VPN connections provide insights into the incoming and outgoing data transfer. A significant drop in these metrics could indicate a problem with the data transmission through the VPN tunnel, such as a routing misconfiguration or an issue with the internet gateway. Monitoring these metrics ensures the data flow is consistent with expected patterns.

What role can Amazon Inspector play in enhancing network visibility and security?

Amazon Inspector is an automated security assessment service that can help improve network visibility and security by assessing the network configuration and behavior of your AWS resources. It evaluates your environment for vulnerabilities or deviations from best practices, such as open ports or improperly configured security groups. While it doesn’t provide direct network performance metrics, it does help ensure that the network is secure and thus can be trusted to perform reliably.

How would you track the efficiency of network packet delivery within your AWS environment?

To track the efficiency of network packet delivery, you can monitor the ‘PacketDropCount’ and ‘PacketForwardCount’ CloudWatch metrics for your Transit Gateway, which give an indication of the packets being dropped versus those successfully routed through the gateway. Additionally, implementing VPC Flow Logs can help analyze packet delivery to and from various instances, allowing for more comprehensive auditing and troubleshooting. Customers may also deploy third-party monitoring tools that can capture and analyze networking packets for more detailed insights.

Describe a scenario in which using AWS CloudTrail in conjunction with CloudWatch would be beneficial for network status monitoring.

AWS CloudTrail is beneficial for auditing and tracking user actions and API usage across AWS infrastructure. In a scenario where unusual network traffic patterns are observed, CloudTrail can provide visibility into which API calls were made that could have potentially led to the change in network traffic. By correlating CloudTrail logs with CloudWatch network metrics, you can identify the cause behind changes in network status, such as the creation of new security group rules or network ACLs that affect network flow. This integration of services helps ensure that changes in network status are intentional and authorized.

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Efe Alnıaçık
5 months ago

Great post! I was wondering, what are the best metrics to monitor VPC performance on AWS?

Ella Mortensen
6 months ago

Great post! AWS CloudWatch definitely is a vital tool for monitoring network metrics in the AWS environment. What specific metrics should we focus on for network performance?

Ferdinand Blanc
7 months ago

Appreciate the detailed post! The explanation on VPC Flow Logs was really helpful. Thanks!

Judith Villagómez
6 months ago

I feel like understanding the concept of CloudWatch Alarms is crucial for real-time network monitoring. Anyone has a checklist?

Anthony Martin
6 months ago

Thanks for the insights! Subnet-level monitoring seems underrated. Any thoughts?

عسل حسینی

What are some best practices when setting up AWS CloudTrail for network visibility?

Kely Fogaça
7 months ago

Great post, very informative!

John Walker
6 months ago

Setting up AWS Direct Connect seems like a complicated process. Any simplified guide?

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