A10 Networks A10 Certified Professional System Administration 4 (A10-SA4)

✅

Reasoning: When the reboot command is executed on the vMaster, the vMaster node itself performs a full reboot. Simultaneously, the vBlades within the aVCS chassis initiate a reload operation, which restarts their ACOS software instances. This ensures synchronization with the vMaster while optimizing chassis availability. ❌ Why the other choices are incorrect:

• Option B is incorrect: A vMaster reboot typically triggers a software reload on vBlades, not a full hardware reboot of all devices in the chassis.
• Option C is incorrect: This choice is incomplete as it fails to describe the concurrent effect on the vBlades, which perform a reload operation.
• Option D is incorrect: The command is executed on the vMaster, meaning the vMaster will reboot, not just the vBlades.

✅

Reasoning: After the initial login establishes a session, all subsequent aXAPI calls must include an Authorization header. This header contains the session ID, a timestamp, and a cryptographic signature to authenticate the request and ensure its integrity. ❌ Why the other choices are incorrect:

• Option B is incorrect: The ACOS device serial number identifies the hardware but is not a standard component of the Authorization header for every API call.
• Option C is incorrect: The programming language used by the client is an implementation detail and irrelevant to the API's authentication mechanism.
• Option D is incorrect: API permissions are handled server-side, tied to the authenticated session, and not submitted as a client-side XML file with every request.
• Option E is incorrect: Log file location is an operational setting or output, not a credential or signature component for authenticating API calls.

✅

Reasoning: A VRRP-A floating-IP address creates a virtual IP presented to the network. This allows upstream routers or client devices to consistently forward traffic to a single IP, abstracting the physical device providing the service and ensuring uninterrupted operation during failover. ❌ Why the other choices are incorrect:

• Option A is incorrect: VRRP-A owner selection primarily relies on configured priorities and preemption, not the floating IP itself.
• Option C is incorrect: VRRP-A hellos typically use the physical interface IP addresses of the participating devices as their source, not the floating IP.
• Option D is incorrect: Management of individual VRRP-A devices is typically performed using their dedicated management IP addresses, not the data plane floating IP.

✅

Reasoning: The vcs vmaster-take-over <priority> command assigns a specific priority for vMaster election. This 200 priority is critically compared against the current vMaster's operating priority (e.g., its default VRID priority) to dynamically determine which blade assumes control of the chassis. This describes the command's core function. ❌ Why the other choices are incorrect:

• Option A is incorrect: The vmaster-take-over command is an administrative override to force a vMaster change. It is designed to take effect, not be ignored, even if the current vMaster is in maintenance mode.
• Option B is incorrect: vmaster-take-over commands are processed individually. A subsequent command with a lower priority might not win the election, but the command itself is not ignored; its priority is still set.
• Option D is incorrect: While 210 is higher than 200, leading vBlade B to likely win, option C describes the fundamental comparison mechanism of the command, which is a more direct answer to "which statement is true" about the command's effect.