3. Host Interface¶
The host
URI contains information about the current operating system
devices, such as the CPU, memory, disk and network. In addition, a
host’s network hostname and system timestamp time are also exposed
through the monitoring interface.
cpu¶
The cpu
resource allows an administrator to view the CPU devices
attached to the host. Selection of the cpu
link in the host
resource generates a list of all CPUs attached to the host, and also an
aggregate all
option.
Notice that AMPS also records CPU statistics for the instance process itself.
Element | Description | Type |
---|---|---|
idle_percent |
Percent of CPU time that the system was waiting for an operation other than an I/O request to complete. | snapshot |
iowait_percent |
Percent of CPU time spent waiting for I/O requests to complete. | snapshot |
system_percent |
Percent of CPU utilization time which occurred while executing kernel processes. | snapshot |
user_percent |
Percent of CPU utilization time which occurred while running at the application level. | snapshot |
Table 3.1: CPU Statistics
Statistics Database Tables: HCPU_STATIC
, HCPU_DYNAMIC
Admin path: /amps/host/cpu/<id>/<metric>
disks¶
The disks
resource lists each of the disk devices attached to the host and permits the inspection of disk usage
statistics. This information is a readily consumable version of the file /proc/diskstats
. Statistics reported are
based on the statistics monitoring update frequency (see the AMPS Configuration Guide for details). This means, for
example, that reads
is the number of disk-reads for the given statistics update interval.
Element | Description | Type |
---|---|---|
filesystem_free_percent |
Percentage of the filesystem currently free. | snapshot |
mount_point |
The mount point for this filesystem. | fixed |
in_progress |
Number of I/O requests waiting to be processed. | snapshot |
read_await |
Average read time completion in milliseconds. | interval average |
write_await |
Average write time completion in milliseconds. | interval average |
Table 3.2: Disks Statistics
Statistics Database Tables: HDISKS_STATIC
, HDISKS_DYNAMIC
Admin path: /amps/host/disks/<id>/<metric>
memory¶
The memory
resource gives details about the system memory statistics. All statistics reported are based on the
current system statistics reported by examining the file /proc/meminfo
. These statistics are updated based on the
statistics monitoring update frequency (see Interval
in AMPS Configuration Reference Guide).
Element | Description | Type |
---|---|---|
available |
The total amount of memory available. Calculated as the sum of free , buffers and
cached . |
snapshot |
buffers |
The amount of physical memory available for file buffers. | snapshot |
cached |
The amount of physical memory used as cache memory. | snapshot |
free |
The amount of physical memory left unused by the system. | snapshot |
in_use |
The amount of memory currently in use. Provided in the admin console, calculated as
total - (free + buffers + cached) . |
snapshot |
swap_free |
The amount of swap memory which is unused. | snapshot |
swap_total |
The total amount of physical swap memory. | fixed |
total |
Total amount of RAM. | fixed |
Table 3.3: Memory Statistics
Statistics Database Tables: HMEMORY_STATIC
, HMEMORY_DYNAMIC
Admin path: /amps/host/memory/<metric>
network¶
The network
resource allows an administrator to examine networking interface statistics on the host. Selecting
the network
resource displays a list of the network interfaces attached to the host. Selecting one of the
interfaces will list the available properties. Reported statistics are rate-based and based on the statistics
monitoring update frequency (see the AMPS Configuration Guide for details). For example, collisions
for
interface eth0
would report the total number of collisions since the last statistics update interval.
Element | Description | Type |
---|---|---|
bytes_in |
Number of bytes received by the interface. | interval snapshot |
bytes_out |
Number of bytes transmitted by the interface. | interval snapshot |
errors |
Total errors both incoming and outgoing. This number includes packets dropped, collisions, fifo, frame, and carrier errors. | interval snapshot |
packets_in |
The total number of packets received by the interface. | interval snapshot |
packets_out |
The total number of packets sent by the interface. | interval snapshot |
Table 3.4: Network Statistics
Statistics Database Tables: HNET_STATIC
, HNET_DYNAMIC
Admin path: /amps/host/network/<id>/<metric>
operating_system¶
The operating_system
resource displays the operating system reported by the host.
Admin path: /amps/host/operating_system
utc_time¶
The utc_time
resource displays the system time on the host. Note: the utc_time
time reflects the time on the
host that the HTTP GET was processed. This differs from all other resources in the host
interface as their update
frequencies are determined by the Interval
tag in the configuration for the Admin interface. For more information
on configuring the Administrative Interface and the Interval
tag, see the AMPS Configuration Guide.
Admin path: /amps/host/utc_time