Understanding High Availability on the NSX Edge Services Gateway

Hello Fellow NSX Operators!

Before I jump into the HA commands, let me briefly preface with a few words about NSX Edge Services Gateway High Availability (simply HA going forward).  You will need to understand the heartbeat path and what type of infrastructure-impacting health events are common to your infrastructure.  You may find yourself troubleshooting High Availability many times because of a change or degradation in the underlying Hosts, Storage or Network.  Be careful with those red herrings.  When HA is implemented with a solid understanding of the underlying infrastructure and its variations, you can enjoy peace of mind in knowing the edge network services are highly available.

This article covers the following topics in regards to HA:
– Implementation considerations
– Troubleshooting commands
– Proactively monitoring HA via syslog

http://www.vmware.com/files/pdf/products/nsx/vmw-nsx-network-virtualization-design-guide.pdf

Edge HA topology graphic from the NSX Network Virtualization design guide


A few HA facts/points/considerations/recommendations…

HA Topology
– It uses an Active/Standby topology.
– When HA is enabled, a second VM is deployed.  The new VM will only be networked to communicate with the primary.
– When HA is disabled, the 2nd VM is destroyed.
  – HA appliances will be deployed based on the user-defined mappings (at these these settings are not dynamic).
– Edge mappings are most easily managed using  /api/4.0/edges/<edgeId>/appliances with the REST api
– Changes appliance settings will trigger an OVF re-deployment of the edge.

HA IP Configuration
– Optional.  If not configured, NSX will assign a valid /30 IP pair using an RFC3927 network.
– If configured manually, valid subnets are system enforced.  10.0.0.0/30 and 10.0.0.1/30 is not valid.  10.0.0.1/30 and 10.0.0.2/30 is valid.

HA vNic Selection
– Optional, it can be left to ANY.
– A minimum of one edge interface is required before enabling HA.
– The recommendation for maximum availability is to configure a network dedicated to the vNIC heartbeating.
– Sharing a vNIC will work without problems as long as the network is not overloaded and available.

HA Timeouts and Heartbeating
  – The default deadtime is 6 seconds
– The current recommended deadtime is 15 seconds (uses a 3 second polling frequency).  There is a tradeoff of service failover time for increased resiliency to lost heartbeats.
– Heartbeats are sent using UDP-694 (the IANA registered port for heartbeats)

HA Appliance Anti-affinity
– Host anti-affinity is handled by system.  When HA is enabled there is a cluster DRS rule added automatically with the name anti-affinity-rule-edge-#, where edge=# is the edge-ID.
anti-affinity
– Storage anti-affinity is not handled by default.  For maximum availability of the edge pair, configure the edge appliances to deploy to different physical storage resources.  Especially important in infrastructure that uses centralized storage.

 


Troubleshooting ESG HA with CLI-based Edge Commands

show service highavailability example output

 nsxe-0> show service highavailability
 Highavailability Status: running
 Highavailability Unit Name: nsxe-0
 Highavailability Unit State: active
 Highavailability Interface(s): vNic_5
 Unit Poll Policy:
    Frequency: 3 seconds
    Deadtime: 15 seconds
 Stateful Sync-up Time: 10 seconds
 Highavailability Healthcheck Status:
    Peer host [vse-1 ]: good
    This host [vse-0 ]: good
 Highavailability Stateful Logical Status:
 File-Sync running
 Connection-Sync running
 xmit        xerr  rcv       rerr
 51219548828 0     42990848  0

show service highavailability connection-sync example output

nsxe-0> show service highavailability connection-sync
connections local:
current active connections: 12693
connections created:            368613263  failed: 0
connections updated:           21695297    failed: 0
connections destroyed:        368600570  failed: 0

connections peer:
current active connections: 0
connections created:          26571 failed: 0
connections updated:         1024 failed: 0
connections destroyed:        26571 failed: 0

traffic processed:
1248602045934 Bytes 6285222215 Pckts

UDP traffic (active device=vNic_5):
51255382200 Bytes sent 43018912 Bytes recv
590146284 Pckts sent 2518471 Pckts recv
0 Error send 0 Error recv

message tracking:
0 Malformed msgs 5863 Lost msgs

show service highavailability connection-sync example output

vse-0> show service highavailability link
Local IP Address: 192.18.0.1/30
Peer IP Address: 192.18.0.2/30

debug packet display / “sniffing” HA heartbeats

Filter using the High Availability vNIC from the root command “show service highavailability”

nsxe-0> debug packet display interface vNic_# port_694
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on vNic_5, link-type EN10MB (Ethernet), capture size 65535 bytes
17:22:50.357722 IP 192.18.0.2.24758 > 192.18.0.1.694: UDP, length 189
17:22:52.709253 IP 192.18.0.1.32165 > 192.18.0.2.694: UDP, length 189
17:22:53.360327 IP 192.18.0.2.24758 > 192.18.0.1.694: UDP, length 190
17:22:55.711667 IP 192.18.0.1.32165 > 192.18.0.2.694: UDP, length 203
17:22:55.711715 IP 192.18.0.1.32165 > 192.18.0.2.694: UDP, length 189
17:22:55.742631 IP 192.18.0.2.24758 > 192.18.0.1.694: UDP, length 203
17:22:56.353520 IP 192.18.0.2.24758 > 192.18.0.1.694: UDP, length 189
17:22:58.716886 IP 192.18.0.1.32165 > 192.18.0.2.694: UDP, length 189
17:22:59.357186 IP 192.18.0.2.24758 > 192.18.0.1.694: UDP, length 189

Viewing Historical HA System Events for an Edge in the Web Client

 

  • Open the vCentter Web Client
  • Open Networking & Security
  • In NSX Edges, double-click the Edge
  • Select the Montor tab
  • Select System Events
  • On the search widget, click the arrow, click Select Columns…
  • Deselect All > Check Module > Type HighAvailability > Click Ok

REST API-based Commands

Query HA Configuration Details on an Edge

GET https://nsxm-ip/api/4.0/edges/edge-#/highavailability/config Example Output

<?xml version="1.0" encoding="UTF-8"?>
<highAvailability>
 <version>6</version>
 <enabled>true</enabled>
 <vnic>2</vnic>
 <ipAddresses>
    <ipAddress>198.18.0.1/30</ipAddress>
    <ipAddress>198.18.0.2/30</ipAddress>
 </ipAddresses>
 <declareDeadTime>15</declareDeadTime>
 <logging>
    <enable>true</enable>
    <logLevel>error</logLevel>
 </logging>
 <security>
 <enabled>false</enabled>
 </security>
</highAvailability>

Delete Edge HA Configuration on an Edge

DELETE https://nsxm-ip/api/4.0/edges/edge-#/highavailability/config

 

Monitoring High Availability Health Proactively

– Open your (vCenter Log Insight ), Splunk or log aggregation solution of choice.
– Build aview of all edge logging (use regex or glob based matches to filter according to your naming convention).

Heartbeat Drops
– Examine matches on the text “lost packet”. Build an alerting rule based on your results.
– When the infrastructure is healthy, there should be not be any HA packets lost.

Example match

Sep 19 11:34:14 nsxe-0 ha[]: [default]: [1371]: WARN: 1 lost packet(s) for [nsxe-0] [37:39]

Late Heartbeats

– Examine matches on the text “Late heartbeat”. Build an alerting rule based on your results.
– Late heartbeats may indicate infrastructure problems.  Possible resource constraints or both edges in the HA pair.
– This can also result in a split brain state.

Example match

Jul  3 09:46:48 nsxe-0 heartbeat: [1454]: WARN: Late heartbeat: Node
nsxe-1: interval 24921 ms

Lost and late heartbeats are the early indicators.  Early indicators are your best friends.  Keep a close eye out for these.

Monitor NSX Manager for Switchover Events

– Filter logging based on NSX Manager SystemEvent, you can use the text [SystemEvent] to filter.
– Examine matches for Event 30202 and 30203 (Edge switching to ACTIVE & STANDBY, respectively)
– Any single event source with more than one or two events should raise a red flag. Any unplanned switchover events should be researched. Build an alerting rule based on your findings.

Example match

Sep 20 20:50:05 nsxm-0 [SystemEvent] Time:'Sat Sep 20 20:49:13.000 GMT 2014', Severity:'High', Event Source:'vm-13950', Code:'30203', Event Message:'vShield Edge HighAvailability switch over happened. VM has moved to STANDBY state.', Module:'vShield Edge HighAvailability'

Split-Brain Indicators 

– Look for the text “returning after partition”; Look for the text “Deadtime value may be too small”
– Matches on these can indicate that the state of HA has most likely entered the split brain state.  Network Services will be mostly unavailable until the condition is resolved.
– Hopefully these do not exist in your environment. Build a preventive alerting rule. Matches are immediately actionable.

That is all folks. Hope this helps.

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NSX SSL VPN-Plus | Adding Client Configurations in Bulk

Anyone using NSX SSL VPN-Plus feature for more than one site will quickly find there is no mechanism for importing client configurations.  The native method for accessing additional sites is to browse to the Gateway for each site (then download and run the installer).

That’s pretty tedious as your site count increases.  There is a better, albeit unsupported, way to manage this need.

SSL VPN-Plus naclient on Windows

In windows, client configuration is stored in the registry.  You can manipulate the windows registry using .reg files.

Open up a text editor, and prepare a file with all of your sites using the following format.  Replace the GatewayList value with your site’s gateway IP address

 Windows Registry Editor Version 5.00

 [HKEY_LOCAL_MACHINE\SOFTWARE\VMware, Inc.\SSL VPN-Plus Client\Connection #1]
 "ConnectionAlias"="site1"
 "BSValue"=dword:00000100
 "GatewayList"="site1-ip:443"

 [HKEY_LOCAL_MACHINE\SOFTWARE\VMware, Inc.\SSL VPN-Plus Client\Connection #2]
 "ConnectionAlias"="site2"
 "BSValue"=dword:00000100
 "GatewayList"="site2_ip:443"

--snip--
 [HKEY_LOCAL_MACHINE\SOFTWARE\VMware, Inc.\SSL VPN-Plus Client\Connection #20]
 "ConnectionAlias"="site20"
 "BSValue"=dword:00000100
 "GatewayList"="site20"

Save the file as a .reg file, the name of the file is arbitrary.

Exit the SSL VPN-Plus naclient application

Import the .reg file

Navigate to HKLM\SOFTWARE\VMware, Inc.\SSL VPN-Plus Client and verify the connections were imported.

Update the ConnectionCount to the total number of sites.  This is important; if the number doesn’t match, naclient will not start.

Start the naclient (C:\Program Files\VMware\SSL VPN-Plus Client\SVPclient.exe)

SSL VPN-Plus naclient on MAC OS X 

This one is easier, the client settings are stored in /opt/sslvpn-plus/naclient/naclient.conf

Quit the naclient application.  Add the site configurations to naclient.conf

vi /opt/sslvpn-plus/naclient/naclient.conf
 site1 site1-ip:443 256 
 site2 site2-ip:443 256 
 --snip--
 site20 site20-ip:443 256

Start the naclient.

That is all peeps.  Have a nice day.

Best (Public) VMware NSX Learning Resources

Let me qualify the title.. I say “best” with the full authority that my opinion carries.  Just trying to give y’all a place to go to get your NSX learn on…

Digital Literature …

VMware Product Walkthroughs – NSX 

The NSX walkthrough is the perfected balance the brevity of a presentation slide-deck with involved hands-on demonstrations.  Very well put together (Check out some of the other walkthroughs).

VMware NSX Design Guide 

The design guide is a PDF~30 pages is a gentle introduction to NSX topologies.  Fundamental read if you’re still trying to get a handle on NSX concepts. 

VMware Network Virtualization Blog

Subject matter content from the experts.  Posts by Martin Casado, Bruce Davie, Brad HedlundRoger Fortier.

VMware Hands on Labs (HOL) Focus: Networking

Get acquainted with NSX Dynamic Routing, the Distributed Firewall & Load Balancing.

VMware NSX 6 Documentation Center

Nothing fancy about this one… ’tis the manuals.  NSX Install and Upgrade Guide & NSX Administration Guide.  Although in the public domain, this resource is extremely difficult (if not impossible) to find via search.  But they are in the public domain.  Whatever is public is not private…right?  

Martin Casado’s Blog – Network Heresy

Scott Lowe’s Blog – Learning NVP/NSX 

Brad Hedlund’s Blog – NSX

If videos are the way you learn …

NSX Architecture Webinar by Ivan Pepelnjak on ipspace.net

VMworld 2013 – Introducing the World to VMware NSX (By Sachin Thakkar)

VMware Interview – Bruce Davie on NSX

VMware NSX Demo

This should at the very least provide a fair start for anyone looking to mentally ramp up for the NSX NVP.

– Gabe