F5 F5CAB4 - BIG-IP Administration Control Plane Administration (F5CAB4) exam

Reporting device status includes monitoring physical resource exhaustion, such as memory. The Control Plane provides both a command-line method via TMSH (show /sys memory) and a graphical method under Statistics > Module Statistics > Memory to report on how memory is allocated across TMM and the Linux host494949494949494949. This is essential for identifying potential "Aggressive Mode" triggers or hardware performance bottlenecks50.

The Control Plane is responsible for ARP (Address Resolution Protocol) management for Virtual Addresses. For a Virtual Server to be reachable, the BIG-IP must respond to ARP requests for that IP. If the "ARP" setting is disabled on the Virtual Address properties, upstream routers cannot resolve the MAC address of the BIG-IP, leading to connectivity failure even if the service itself is "Available."

In a BIG-IP Device Service Cluster (DSC), manual configuration synchronization is performed using the ConfigSync framework. The supported and documented command to manually push the local configuration to a specific device group is:

tmsh run cm config-sync to-group

This command:

Initiates a one-time manual ConfigSync

Pushes the local device’s configuration to all members of the specified device group

Is commonly used when auto-sync is disabled or when the administrator wants explicit control over synchronization timing

Why the other options are incorrect:

A is not a valid TMSH command for ConfigSync.

B enables auto-sync but does not perform an immediate synchronization.

D is not a valid or supported TMSH command for device group configuration synchronization.

Therefore, the correct command to manually synchronize configuration to a device group is C.

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The User Configuration Set (UCS) is a flexible tool designed by the Control Plane to handle various lifecycle management scenarios, including upgrades and hardware migrations.

Version Compatibility (Option B): TMOS is designed to be backward compatible. The Control Plane can ingest a UCS file created on an older version of software and automatically upgrade the configuration objects to match the current, later version during the restore process.

Platform Portability (Option C): While a UCS archive contains platform-specific information, the BIG-IP system allows for "platform-independent" restores. This is a vital procedural concept for migrating from one hardware model to another or from physical hardware to a Virtual Edition (VE).

Management of State: When restoring to a different platform or a later version, the administrator often uses specific flags (such as no-license or platform-migrate in later versions) to ensure that only the portable configuration data is applied while preserving the new platform's unique identifiers.

To determine the current failover (HA) status of a BIG-IP system using tmsh, F5 documentation explicitly states that the administrator should use the following command:

show /cm failover-status

This command displays:

The current failover state (active, standby, or offline)

Detailed failover status information

The operational HA condition of the device within a device group

According to F5 Knowledge Base Article K08452454, the documented procedure for checking failover status is:

Log in to the TMOS Shell (tmsh)

Run show /cm failover-status

Why the other options are incorrect:

A. list /cm failover shows configuration settings, not operational HA status.

B. show /sys failover is not the documented command for checking current failover status and does not align with F5’s recommended procedure.

The EUD is a 33hardware-level diagnostic tool that runs outside of the TMOS operating system. Because it is used when the system cannot boot or is in a pre-boot state, it cannot be accessed via the GUI or management network. The administrator must connect physically via the serial Console Port to interact with the boot menu and initiate the hardware tests.

A BIG-IP device group cannot be deleted if it still contains device members, even if one of those devices has already been decommissioned or is unreachable. Before deleting the device group, the administrator must explicitly remove the decommissioned device from the device group configuration.

Once the removed or unreachable device is deleted from the device group membership, the BIG-IP system allows the remaining administrator to successfully delete the device group.

Why the other options are incorrect:

A. Remove all members from the device groupThis is not required; the key requirement is removing the decommissioned device, not all members.

B. Make sure all members are in syncSynchronization status does not prevent device group deletion.

D. Disable the device groupDevice groups cannot be disabled; they must be modified or deleted.

Therefore, the correct prerequisite action is to remove the decommissioned device from the device group, making C the correct answer.

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The BIG-IP Control Plane monitors the "Commit ID" of the configuration on all group members. When a change is made on the Standby unit, it becomes the member with the most recent configuration. The "Recommended Action" in the HA status dashboard will be to synchronize that specific device's configuration to the rest of the group to ensure consistency

On BIG-IP systems, all authentication attempts for administrative access—including logins to the Configuration Utility (GUI)—are logged in /var/log/secure. This log file records:

Successful and failed login attempts

The username used

The authentication method (local, LDAP, RADIUS, etc.)

Access denials and PAM authentication errors

Why the other options are incorrect:

/var/log/pam/tallylog tracks account lockouts and failed attempt counters, not detailed login attempts.

/var/log/ltm logs traffic management events, not administrative authentication.

/var/log/httpd logs web server activity but does not record authentication success or failure for BIG-IP administrative users.

Therefore, the correct log file to verify whether a user attempted to log in to the BIG-IP Configuration Utility is /var/log/secure.

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In F5 TMOS, administrative roles and user permissions are partition-specific. The User Manager role allows an account to manage other user accounts, but this authority is restricted to the administrative partitions to which the User Manager has been granted access.

Partition Awareness: If User1 (the User Manager) attempts to modify User2 and fails, while the full Administrator succeeds, it indicates that User2 resides in a partition where User1 does not have management rights.

Principle of Least Privilege: This principle dictates that a user should be given only the minimum level of access necessary to perform their job functions.

Procedural Solution: Granting "Administrator" privileges (Option B) would violate least privilege by giving User1 full control over all system settings and all partitions. Moving users between partitions (Options A and C) might disrupt the organizational security structure. The correct and most secure administrative action is to modify the partition access for User1 to include the partition where User2 is located. This enables User1 to manage User2’s properties while maintaining their restricted role as a User Manager.