A10 ACOS flashcards
A10 ACOS · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- ACOS
- A10's 64-bit, Linux-based network operating system that runs on Thunder hardware and vThunder virtual appliances and provides ADC, SSL, and HA features through a common CLI and GUI.
- User EXEC mode
- The initial CLI mode, shown by the > prompt, which allows basic show commands but not configuration changes; use enable to reach Privileged EXEC mode.
- Privileged EXEC mode
- The CLI mode reached with enable, shown by the # prompt; it permits show, write memory, reload, and other administrative commands, and configure terminal enters global configuration.
- write memory
- The ACOS command that copies the running configuration into the startup configuration, so changes survive a reload; it is the CLI equivalent of saving.
- Management interface
- A dedicated Ethernet interface or VLAN used for administrative traffic such as SSH, HTTPS GUI, NTP, syslog, and licensing, kept separate from client data-plane forwarding.
- show tech-support
- An ACOS diagnostic command that collects configuration, logs, process status, and system details into a support bundle for troubleshooting or opening a vendor case.
- Default admin credentials
- A10 devices ship with a default administrative account (commonly admin/a10) that must be changed during initial access to prevent unauthorized GUI, SSH, or console login.
- Virtual server
- An ACOS object that defines a client-facing VIP address and port/protocol; it receives client traffic and forwards it to bound service groups or backend members.
- Service group
- A logical pool of backend servers and ports that share a load-balancing method and health monitor; a virtual server port binds to one or more service groups.
- Round-robin method
- A load-balancing algorithm that sends each new connection to the next member in sequence, distributing traffic evenly when members have equal capacity and health.
- Least-connection method
- A load-balancing algorithm that assigns each new connection to the member with the fewest active connections, which suits backends with unequal or variable request costs.
- Source-IP persistence
- A persistence template that hashes or records the client source IP so subsequent connections from that client go to the same backend member until the timeout expires.
- Member weight
- A numeric value, default 1, used by weighted load-balancing methods; higher weights give a member a proportionally larger share of new connections.
- Connection limit
- A configurable cap on concurrent connections applied at virtual-server, port, service-group, or member level; excess connections may be queued or rejected depending on settings.
- Health monitor
- A named ACOS object that probes a backend using a method such as TCP, HTTP, or ICMP at a set interval and marks the member Up or Down based on results.
- Health-check retry
- The number of consecutive failed probes ACOS requires before marking a backend member Down; it prevents a single dropped probe from removing a healthy server.
- Up-retry
- The number of consecutive successful probes ACOS requires before marking a previously Down member Up again, preventing flapping servers from receiving traffic too early.
- HTTP health check
- A monitor that sends an HTTP request and validates the response, such as a 200 status code, proving the web application responds rather than only the TCP port.
- Disable member
- An ACOS maintenance action that stops new connections from being sent to a server or member while leaving its configuration and health-check settings intact for re-enabling.
- Health-check disable
- A per-member setting that stops ACOS from probing that member; the member remains eligible for load balancing, so it is not a traffic-drain operation.
- SSL offload
- Terminating client TLS at the ACOS virtual server, decrypting traffic, and forwarding plain HTTP to backends; this reduces backend CPU load but changes the encryption boundary.
- Client-SSL template
- An ACOS template bound to an HTTPS virtual-server port that holds the certificate, key, chain, TLS versions, ciphers, and client-authentication settings used for front-end termination.
- Server-SSL template
- An ACOS template bound to a service group or server port that re-encrypts traffic from ACOS to the backend, enabling end-to-end TLS when offload alone is not acceptable.
- Certificate chain
- The ordered set of the server leaf certificate and intermediate CA certificates; clients need the intermediates to build a trusted path to a root CA.
- Private key match
- The requirement that the installed private key mathematically corresponds to the server certificate; a mismatch causes TLS handshake failures because ACOS cannot prove ownership.
- Client certificate authentication
- A TLS setting where ACOS requests a client certificate and validates it against a configured CA certificate, adding mutual authentication beyond server-only TLS.
- VRRP-A
- A10's enhanced VRRP-based high-availability mechanism; peers exchange advertisements, and a floating IP moves to the standby device if the active peer fails.
- device-id and set-id
- VRRP-A parameters: device-id uniquely identifies each peer, while set-id must match on both peers so they form the same HA group.
- Preempt mode
- A VRRP-A setting that lets a higher-priority peer reclaim the active role after recovery; disabling preemption keeps the current active device until a failure occurs.
- Floating IP
- A virtual IP address owned by the active VRRP-A peer and moved to the standby during failover, allowing clients and servers to use a consistent gateway or VIP.
- Configuration synchronization
- The practice of keeping both HA peers' running and startup configurations identical, including certificates, virtual servers, and health monitors, so failover behavior is consistent.
- Syslog host
- A remote logging destination configured on ACOS so system, health-check, and HA events are exported off-box for retention, correlation, and alerting.