htools1
Cluster allocation and placement tools for ganeti
Usage
hbal-
hbal cluster balancer
hspace-
hspace cluster capacity computation
hail-
hail IAllocator plugin
hscan-
hscan saves cluster state for later reuse
Overview
htools is a suite of tools designed to help with allocation/movement of instances and balancing of Ganeti clusters. htools is also the generic binary that must be symlinked or hardlinked under each tool's name in order to perform the different functions. Alternatively, the environment variable HTOOLS can be used to set the desired role.
Installed as hbal, it computes and optionally executes a suite of instance moves in order to balance the cluster.
Installed as hspace, it computes how many additional instances can be fit on a cluster, while maintaining N+1 status. It can run on models of existing clusters or of simulated clusters.
Installed as hail, it acts as an IAllocator plugin, i.e. it is used by Ganeti to compute new instance allocations and instance moves.
Installed as hscan, it scans the local or remote cluster state and saves it to files which can later be reused by the other roles.
Options
Options behave the same in all program modes, but not all program modes support all options. Some common options are:
-
-p, --print-nodes -
Prints the node status, in a format designed to allow the user to understand the node's most important parameters. If the command in question makes a cluster transition (e.g. balancing or allocation), then usually both the initial and final node status is printed.
It is possible to customise the listed information by passing a comma-separated list of field names to this option (the field list is currently undocumented), or to extend the default field list by prefixing the additional field list with a plus sign. By default, the node list will contain the following information:
- F
-
a character denoting the status of the node, with '-' meaning an offline node, '*' meaning N+1 failure and blank meaning a good node
Name-
the node name
t_mem-
the total node memory
n_mem-
the memory used by the node itself
i_mem-
the memory used by instances
x_mem-
amount memory which seems to be in use but cannot be determined why or by which instance; usually this means that the hypervisor has some overhead or that there are other reporting errors
f_mem-
the free node memory
r_mem-
the reserved node memory, which is the amount of free memory needed for N+1 compliance
t_dsk-
total disk
f_dsk-
free disk
pcpu-
the number of physical cpus on the node
vcpu-
the number of virtual cpus allocated to primary instances
pcnt-
number of primary instances
scnt-
number of secondary instances
p_fmem-
percent of free memory
p_fdsk-
percent of free disk
r_cpu-
ratio of virtual to physical cpus
lCpu-
the dynamic CPU load (if the information is available)
lMem-
the dynamic memory load (if the information is available)
lDsk-
the dynamic disk load (if the information is available)
lNet-
the dynamic net load (if the information is available)
-
-v, --verbose -
Increase the output verbosity. Each usage of this option will increase the verbosity (currently more than 2 doesn't make sense) from the default of one.
-
-q, --quiet -
Decrease the output verbosity. Each usage of this option will decrease the verbosity (less than zero doesn't make sense) from the default of one.
-
-V, --version -
Just show the program version and exit.
Units
Some options accept not simply numerical values, but numerical values together with a unit. By default, such unit-accepting options use mebibytes. Using the lower-case letters of m, g and t (or their longer equivalents of mib, gib, tib, for which case doesn't matter) explicit binary units can be selected. Units in the SI system can be selected using the upper-case letters of M, G and T (or their longer equivalents of MB, GB, TB, for which case doesn't matter).
More details about the difference between the SI and binary systems can be read in the units(7) man page.
Environment
The environment variable HTOOLS can be used instead of renaming/symlinking the programs; simply set it to the desired role and then the name of the program is no longer used.