Cisco NAC Appliance - Clean Access Manager Installation and Configuration Guide, Release 4.1(2)
Configuring High Availability
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Configuring High Availability (HA)

Table Of Contents

Configuring High Availability (HA)

Overview

Before Starting

Connect the Clean Access Manager Machines

Serial Connection

Configure the HA-Primary CAM

Configure the HA-Secondary CAM

Complete the Configuration

Upgrading an Existing Failover Pair

Failing Over an HA-CAM Pair

Useful CLI Commands for HA

Adding High Availability Cisco NAC Appliance To Your Network


Configuring High Availability (HA)


This chapter describes how to set up a pair of Clean Access Manager machines for high-availability. By deploying Clean Access Managers in high-availability mode, you can ensure that important monitoring, authentication, and reporting tasks continue in the event of an unexpected shutdown. Topics include:

Overview

Before Starting

Connect the Clean Access Manager Machines

Configure the HA-Primary CAM

Configure the HA-Secondary CAM

Upgrading an Existing Failover Pair

Failing Over an HA-CAM Pair

Useful CLI Commands for HA

Adding High Availability Cisco NAC Appliance To Your Network

Overview

The following key points provide a high-level summary of HA-CAM operation:

The Clean Access Manager high-availability mode is an Active/Passive two-server configuration in which a standby CAM machine acts as a backup to an active CAM machine.

The active Clean Access Manager performs all tasks for the system. The standby CAM monitors the active CAM and keeps its database synchronized with active CAM's database.

Both CAMs share a virtual Service IP for the eth0 trusted interface. The Service IP should be used for the SSL certificate.

The primary and secondary CAM machines exchange UDP heartbeat packets every 2 seconds. If the heartbeat timer expires, stateful failover occurs.

The eth1 interface and/or serial interface on the CAMs can be used for heartbeat packets and database synchronization. If both eth1 and serial interfaces are configured for heartbeat, both interfaces need to fail for failover to occur.

Figure 15-1 illustrates a sample configuration.

Figure 15-1 Clean Access Manager Example High-Availability Configuration

The Clean Access Manager high-availability mode is an Active/Passive two-server configuration in which a standby Clean Access Manager machine acts as a backup to an active Clean Access Manager machine. While the active CAM carries most of the workload under normal conditions, the standby monitors the active CAM and keeps its data store synchronized with the active CAM's data.

If a failover event occurs, such as the active CAM shuts down or stops responding to the peer's "heartbeat" signal, the standby assumes the role of the active CAM.

When first configuring the HA peers, you must specify an HA-Primary CAM and HA-Secondary CAM. Initially, the HA-Primary is the active CAM, and the HA-Secondary is the standby (passive) CAM, but the active/passive roles are not permanently assigned. If the primary CAM goes down, the secondary (standby) becomes the active CAM. When the original primary CAM restarts, it assumes the backup role.

When the Clean Access Manager starts up, it checks to see if its peer is active. If not, the starting CAM assumes the active role. If the peer is active, on the other hand, the starting CAM becomes the standby.

You can configure two Clean Access Managers as an HA pair at the same time, or you can add a new Clean Access Manager to an existing standalone CAM to create a high-availability pair. In order for the pair to appear to the network and to the Clean Access Servers as one entity, you must specify a Service IP address to be used as the trusted interface (eth0) address for the HA pair. This Service IP address is also used to generate the SSL certificate.


Note If both the HA-Primary and HA-Secondary CAMs in your HA deployment lose their configuration, you can restore the system using the guidelines in Restoring Configuration from CAM Snapshot In HA Deployment, page 14-36.


To create the crossover network on which high-availability information is exchanged, you connect the eth1 ports of both CAMs and specify a private network address not currently routed in your organization (the default HA crossover network is 192.168.0.252). The Clean Access Manager then creates a private, secure two-node network for the eth1 ports of each CAM to exchange UDP heartbeat traffic and synchronize databases. Note that the CAM always uses eth1 as the UDP heartbeat interface.

For extra security, you can also connect the serial ports of each Clean Access Manager for heartbeat exchange. In this case, both the UDP heartbeat and serial heartbeat interfaces must fail for the standby system to take over.


Warning When connecting high availability (failover) pairs via serial cable, BIOS redirection to the serial port must be disabled for NAC-3300 series appliances and any other server hardware platform that supports the BIOS redirection to serial port functionality. See Supported Hardware and System Requirements for Cisco NAC Appliance (Cisco Clean Access) for more information.



Note For serial cable connection for HA (either HA-CAM or HA-CAS), the serial cable must be a "null modem" cable. For details, refer to http://www.nullmodem.com/NullModem.htm.


The following sections describe the steps for setting up high availability.


Note The instructions in this section assume that you are adding a Clean Access Manager to a standalone CAM in order to configure the HA pair for a test network.


Before Starting


Warning To prevent any possible data loss during database synchronization, always make sure the standby (secondary) Clean Access Manager is up and running before failing over the active (primary) Clean Access Manager.


Before configuring high availability, ensure that:

You have obtained a high-availability (failover) license.


Note When installing a CAM Failover (HA) license, install the Failover license to the Primary CAM first, then load all the other licenses.


Both CAMs are installed and configured (see Perform the Initial Configuration, page 2-7.)

For heartbeat, each CAM needs to have a unique hostname (or node name). For HA CAM pairs, this host name will be provided to the peer, and must be resolved via DNS or added to the peer's /etc/hosts file.

You have a CA-signed certificate for the Service IP of the HA CAM pair. (For testing, you can use the CA-signed certificate of the HA-Primary CAM, but this requires additional steps to configure the HA-Primary CAM's IP as the Service IP).

The HA-Primary CAM is fully configured for runtime operation. This means that connections to authentication sources, policies, user roles, access points, and so on, are all specified. This configuration is automatically duplicated in the HA-Secondary (standby) CAM.

Both Clean Access Managers are accessible on the network (try pinging them to test the connection).

The machines on which the CAM software is installed have a free Ethernet port (eth1) and at least one free serial port. Use the specification manuals for the server hardware to identify the serial port (ttyS0 or ttyS1) on each machine.

In Out-of-Band deployments, Port Security is not enabled on the switch interfaces to which the CAS and CAM are connected. This can interfere with CAS HA and DHCP delivery.

The following procedures require you to reboot the Clean Access Manager. At that time, its services will be briefly unavailable. You may want to configure an online CAM when downtime has the least impact on your users.


Note Cisco NAC Appliance web admin consoles support the Internet Explorer 6.0 or above browser.


Connect the Clean Access Manager Machines

There are two types of connections between HA-CAM peers: one for exchanging runtime data relating to the Clean Access Manager activities and one for the heartbeat signal. In High Availability, the Clean Access Manager always uses the eth1 interface for both data exchange and heartbeat UDP exchange. When the UDP heartbeat signal fails to be transmitted and received within a certain time period, the standby system takes over. In order to provide an extra measure of security, it is highly recommended to add a serial heartbeat connection between the Clean Access Manager peers. The serial connection provides an additional dedicated heartbeat exchange method that must fail before the standby system can take over. However, note that the eth1 connection between the CAM peers is mandatory.

Physically connect the peer Clean Access Managers as follows:

Use crossover cable to connect the eth1 Ethernet ports of the Clean Access Manager machines. This connection is used for the heartbeat UDP interface and data exchange (database mirroring) between the failover peers.

Use null modem serial cable to connect the serial ports (highly recommended). This connection is used as an additional heartbeat serial exchange (keep-alive) between the failover peers.


Note For serial cable connection for HA, the serial cable must be a "null modem" cable. For details, refer to http://www.nullmodem.com/NullModem.htm.


Serial Connection

If the machine running the Clean Access Manager software has two serial ports, you can use the additional port for the serial heartbeat connection. By default, the first serial port detected on the CAM server is configured for console input/output (to facilitate installation and other types of administrative access).

If the machine has only one serial port (COM1 or ttyS0), you can reconfigure the port to serve as the high-availability heartbeat connection. This is because, after the CAM software is installed, SSH or KVM console can always be used to access the command line interface of the CAM.


Warning When connecting high availability (failover) pairs via serial cable, BIOS redirection to the serial port must be disabled for NAC-3300 series appliances and any other server hardware platform that supports the BIOS redirection to serial port functionality. See Supported Hardware and System Requirements for Cisco NAC Appliance (Cisco Clean Access) for more information.


You can enable/disable the serial port using the Disable Serial Login checkbox on the HA CAM settings (under Administration > Clean Access Manager > Network & Failover | Failover Settings | Disable Serial Login). When there is only one serial port on the CAM machine, this checkbox allows administrators to disable serial login on COM1 so that it can be used as the Heartbeat Serial Interface for a pair of HA-Clean Access Managers.


Note Serial login is enabled by default on the CAM. If you are using COM1 for the Heartbeat Serial Interface of the CAM, you must click the Disable Serial Login checkbox to disable serial login on COM1.


Configure the HA-Primary CAM

Once you have verified the prerequisites, perform the following steps to configure the Clean Access Manager as the HA-Primary for the high availability pair. See Figure 15-1 for a sample configuration example.

1. Open the web admin console for the Clean Access Manager to be designated as the HA-Primary, and go to Administration > CCA Manager > SSL Certificate to configure the SSL certificate for the primary CAM. The Generate Temporary Certificate form appears.


Note The HA configuration steps in this chapter assume that a temporary certificate will be exported from the HA-Primary CAM to the HA-Secondary CAM.


If using a temporary certificate for the HA pair:

a. Complete the Generate Temporary Certificate form and click Generate.
The certificate must be generated for the Service IP address of the HA pair.

b. When finished generating the temporary certificate, choose Export CSR/Private Key/Certificate from the Choose an action menu.

c. Click the Export button for Currently Installed Private Key to export the SSL private key. Save the key file to disk. You will have to import this key into the HA-Secondary CAM later.

d. Click the Export button for Currently Installed Certificate to export the current SSL certificate. Save the certificate file to disk. You will have to import this certificate file into the HA-Secondary CAM later.

If using a CA-signed certificate for the HA pair:


Note The CA-signed certificate must either be based on the Service IP or a hostname/domain name resolvable to the Service IP through DNS. See Manage CAM SSL Certificates, page 14-5 for details.


a. Select Import Certificate from the Choose an action: menu.

b. Use the Browse button next to the Certificate File field and navigate to the CA-signed cert.

c. Choose CA-signed PEM-encoded X.509 Cert from the File Type dropdown menu:

d. Click Upload to import the certificate. Note that you will need to import this same certificate into the HA-Secondary CAM later.

e. Click Verify and Install Uploaded Certificates.

f. Select Export CSR/Private Key/Certificate from the Choose an action dropdown list.

g. Click the Export button for the Currently Installed Private Key to export the SSL private key associated with the CA-signed certificate. Save the key file to disk. You will need to import this file into the HA-Secondary CAM later.

2. Go to Administration > CCA Manager and click the Network & Failover tab. Choose the HA-Primary option from the High-Availability Mode dropdown menu. The high availability settings appear:

Figure 15-2 Network & Failover Settings for the CAM

3. Copy the value from the IP Address field under Network Settings and enter it in Service IP Address field. The Network Settings IP Address is the existing IP address of the current Clean Access Manager. The idea here is to turn this IP address, which the Clean Access Servers already recognize, into the virtual Service IP address for the Clean Access Manager pair.

Figure 15-3 Configuring the Service IP

4. Change the IP address under Network Settings to an available address (for example n.152)

Figure 15-4 Configuring New IP Address

5. Each Clean Access Manager must have a unique host name (such as camanager1 and camanager2). Type the host name of the HA-Primary CAM in the Host Name field under Network Settings, and type the host name of the HA-Secondary CAM in the Peer Host Name field under Failover Settings.

Figure 15-5 Example Primary Clean Access Manager Failover Settings


NoteA Host Name value is mandatory when setting up high availability, while the Host Domain name is optional.

The Host Name and Peer Host Name fields are case-sensitive. Make sure to match what is typed here with what is typed for the HA-Secondary CAM later.


6. From the Heartbeat Serial Interface dropdown menu, choose the serial port to which you connected the serial cable of the HA-Primary CAM, or leave this N/A if not using serial connection.

7. If your machine only has one serial port and you are using COM1 as the Heartbeat Serial Interface, you must check the Disable Serial Login checkbox to ensure serial login is disabled on COM1. See Serial Connection for further details.

8. To maintain synchronization, the Clean Access Manager peers exchange data by a crossover network. You must specify a private network address space not currently routed in your organization in the Crossover Network field (such as 10.10.10). The default crossover network provided is 192.168.0.252. If this address conflicts with your network, make sure to specify a different private address space. For example, if your organization uses the private network 192.168.151.0, use 10.1.1.x as the crossover network. The subnet mask and last octet of the IP address are fixed, so only enter the network portion of the IP address in the Crossover Network field.

9. Click Update and then Reboot to restart the Clean Access Manager.

After the Clean Access Manager restarts, make sure that the CAM machine is working properly. Check to see if the Clean Access Servers are connected and new users are being authenticated.

Configure the HA-Secondary CAM

1. Open the web admin console for the Clean Access Manager to be designated as the HA-Secondary, and go to Administration > CCA Manager > SSL Certificate.

2. Before starting:

Back up the secondary CAM's private key

Make sure the private key and SSL certificate files associated with the Service IP/HA-Primary CAM are available (previously exported as described in Configure the HA-Primary CAM).

3. Import the HA-Primary CAM's private key file and certificate as described below:

a. In the SSL Certificate tab, choose Import Certificate from the Choose an action: menu

b. Click Browse next to the Certificate File field, and browse to your backup copy of the private key file generated with the certificate that will be used for the HA pair.

c. Choose Private Key as the File Type.

d. Click Upload to upload the private key.

e. With Import Certificate selected from the Choose an action: menu, browse to the certificate (temporary or CA-signed) associated with the private key.

f. Choose CA-signed PEM-encoded X.509 Cert as the File Type.

g. Click Upload to upload the temporary certificate or CA-signed certificate.

h. Click Verify and Install Uploaded Certificates.

See Manage CAM SSL Certificates, page 14-5 for details.

4. Go to the Administration > CCA Manager > Network & Failover | Network Settings and change the IP Address of the secondary CAM to an address that is different from the HA-Primary CAM IP address and the Service IP address (such as n.153).

Figure 15-6 Example HA-Secondary Clean Access Manager Failover Settings

5. Set the Host Name value under Network Settings to the same value set for the Peer Host Name in the HA-Primary CAM configuration. See Figure 15-5.


Note The Host Name and Peer Host Name fields are case-sensitive. Make sure to match what is typed here with what was typed for the HA-Primary CAM.


6. Choose HA-Secondary in the High-Availability Mode dropdown menu. The high availability settings appear.

7. Set the Service IP Address value under Failover Settings to the same value set for the Service IP Address in the HA-Primary CAM configuration.

8. Set the Peer Host Name value under Failover Settings to the HA-Primary CAM's host name.

9. From the Heartbeat Serial Interface dropdown menu, choose the serial port to which you connected the serial cable of the HA-Primary CAM, or leave this N/A if not using serial connection.


Warning When connecting high availability (failover) pairs via serial cable, BIOS redirection to the serial port must be disabled for NAC-3300 series appliances and any other server hardware platform that supports the BIOS redirection to serial port functionality. See Supported Hardware and System Requirements for Cisco NAC Appliance (Cisco Clean Access) for more information.


10. If your machine only has one serial port and you are using COM1 as the Heartbeat Serial Interface, you must check the Disable Serial Login checkbox to ensure serial login is disabled on COM1. See Serial Connection for further details.

11. Type the same Crossover Network Interface Settings as you entered for the HA-Primary CAM.

12. Click Update and then Reboot.

When the standby CAM starts up, it automatically synchronizes its database with the active CAM.

Finally, open the admin console for the standby again and complete the configuration as follows. Notice that the admin console for the standby now has only one management module.

Figure 15-7 Standby Web Admin Console

Complete the Configuration

1. Verify settings in the Network & Failover page for the standby CAM.

The high availability configuration is now complete.

Upgrading an Existing Failover Pair

For instructions on how to upgrade an existing failover pair to a new CCA release, see "Upgrading High Availability Pairs" in the Release Notes for Cisco NAC Appliance (Cisco Clean Access), Version 4.1(x).

Failing Over an HA-CAM Pair


Warning To prevent any possible data loss during database synchronization, always make sure the standby CAM is up and running before failing over the active CAM.


To failover an HA-CAM pair, SSH to the active machine in the pair and perform one of the following commands:

shutdown, or

reboot, or

service perfigo stop

This stops all services on the active machine. When heartbeat fails, the standby machine will assume the active role. Perform service perfigo start to restart services on the stopped machine. This should cause the stopped machine to assume the standby role.


Note service perfigo restart should not be used to test high availability (failover). Instead, Cisco recommends "shutdown" or "reboot" on the machine to test failover, or, the CLI commands service perfigo stop and service perfigo start. See Using the Command Line Interface (CLI), page 2-10.


Useful CLI Commands for HA

The following are useful directories to know about for HA on the CAM:

/etc/ha.d/perfigo/conf

/etc/ha.d/ha.cf

The following example shows the location of the HA debug/log files, as well as the name of each CAM (node) in the HA pair:

[root@cam1 ha.d]# more ha.cf
# Generated by make-hacf.pl
udpport         694
bcast           eth1
auto_failback   off
apiauth         default uid=root
log_badpack     false
debug           0
debugfile       /var/log/ha-debug
logfile         /var/log/ha-log
#logfacility    local0
watchdog        /dev/watchdog
keepalive       2
warntime        10
deadtime        15
node            cam1
node            cam2

Verifying Active/Standby Runtime Status on the HA CAM

The following example shows how to use the CLI to determine the runtime status (active or standby) of each CAM in the HA pair. You can generally find the fostate.sh command from the /store directory of your last upgrade, for example, /store/cca_upgrade-4.x.x.

1. Run the fostate.sh script on the first CAM:

[root@cam1 cca_upgrade-4.x.x]# ./fostate.sh 
My node is active, peer node is standby
[root@cam1 cca_upgrade-4.x.x]# 

This CAM is the active CAM in the HA-pair

2. Run the fostate.sh script on the second CAM:

[root@cam2 cca_upgrade-4.x.x]# ./fostate.sh 
My node is standby, peer node is active
[root@cam2 cca_upgrade-4.x.x]# 

This CAM is the standby CAM in the HA-pair

Verifying Primary/Secondary Configuration Status on the HA CAM

The following example shows how to use the CLI to determine the HA mode (Primary/Secondary) for which each CAM was initially configured in the HA pair.

1. Find the name of the CAMs (nodes) with /etc/ha.d/ha.cf.

2. Then check status on each CAM, for example:

[root@cam1 ~]# /perfigo/control/bin/check-ha cam1
active
[root@cam1 ~]# /perfigo/control/bin/check-ha cam2
active

3. Go to /perfigo/control/tomcat and perform ls -la:

If webapps is pointing to normal-webapps, it is the primary CAM

If webapps is pointing to admin-webapps, it is the secondary CAM

For example, this CAM is the primary CAM:

[root@cam1 tomcat]# cd /perfigo/control/tomcat
[root@cam1 tomcat]# ls -la
	total 216
	drwxr-xr-x  12 root root  4096 Sep 14 23:28 .
	drwxr-xr-x   8 root root  4096 Aug 28 22:12 ..
	drwxr-xr-x   4 root root  4096 Aug 28 22:12 admin-webapps
	<output cut.....>
	drwxr-xr-x   2 root root  4096 Aug 28 22:12 temp
	lrwxrwxrwx   1 root root    38 Sep 14 23:28 webapps -> 
/perfigo/control/tomcat/normal-webapps
	drwxr-xr-x   3 root root  4096 Aug 28 15:15 work

This CAM is the secondary CAM:

[root@cam2 tomcat]# ls -la
	total 216
	drwxr-xr-x  12 root root  4096 Sep 14 23:33 .
	drwxr-xr-x   8 root root  4096 Sep 15  2006 ..
	drwxr-xr-x   4 root root  4096 Sep 15  2006 admin-webapps
	<output cut ...>
	drwxr-xr-x   2 root root  4096 Sep 15  2006 temp
	lrwxrwxrwx   1 root root    37 Sep 14 23:33 webapps -> 
/perfigo/control/tomcat/admin-webapps
	drwxr-xr-x   3 root root  4096 Sep 14 23:25 work

Adding High Availability Cisco NAC Appliance To Your Network

The following diagrams illustrate how HA-CAMs and HA-CASs can be added to an example core-distribution-access network (with Catalyst 6500s in the distribution and access layers).

Figure 15-8 shows a network topology without Cisco NAC Appliance, where the core and distribution layers are running HSRP (Hot Standby Router Protocol), and the access switches are dual-homed to the distribution switches.

Figure 15-8 Example Core-Distribution-Access Network Before Cisco NAC Appliance

Figure 15-9 shows how HA-CAMs can be added to the core-distribution-access network. In this example, the HA heartbeat connection is configured over both serial and eth1 interfaces.

Figure 15-9 Adding HA CAMs to Network

Figure 15-10 shows how HA-CASs can be added to the core-distribution-access network. In this example, the CAS is configured as an L2 OOB Virtual Gateway in Central Deployment. The HA heartbeat connection is configured over both a serial interface and a dedicated eth2 interface. Link-failure based failover connection can also be configured over the eth0 and/or eth1 interfaces.


Note Cisco NAC network modules installed in Cisco Integrated Services Routers (ISRs) do not support high availability.


Figure 15-10 Adding HA CAS to Network