Provided by: ganeti-htools-2.16_2.16.0-5ubuntu1_amd64 bug

NAME

       hspace - Cluster space analyzer for Ganeti

SYNOPSIS

       hspace   {backend   options...}   [algorithm   options...]  [request  options...]  [output
       options...] [-v...  | -q]

       hspace --version

       Backend options:

       { -m cluster | -L[ path ] | -t data-file | --simulate spec | -I path }

       Algorithm options:

       [ --max-cpu cpu-ratio ] [ --min-disk disk-ratio ] [ -O name... ] [ --independent-groups  ]
       [ --no-capacity-checks ]

       Request options:

       [--disk-template template ]

       [--standard-alloc disk,ram,cpu ]

       [--tiered-alloc disk,ram,cpu ]

       Output options:

       [--machine-readable[=*CHOICE*] ] [-p[fields]]

DESCRIPTION

       hspace  computes  how many additional instances can be fit on a cluster, while maintaining
       N+1 status.

       The program will try to place instances, all of the same size, on the cluster,  until  the
       point  where we don't have any N+1 possible allocation.  It uses the exact same allocation
       algorithm as the hail iallocator plugin in allocate mode.

       The output of the program is designed either for human consumption (the default) or,  when
       enabled  with  the  --machine-readable  option  (described  further  below),  for  machine
       consumption.  In the latter case, it is intended to interpreted as a  shell  fragment  (or
       parsed  as  a key=value file).  Options which extend the output (e.g.  -p, -v) will output
       the additional information on stderr (such that the stdout is still parseable).

       By default, the instance specifications  will  be  read  from  the  cluster;  the  options
       --standard-alloc and --tiered-alloc can be used to override them.

       The  following  keys  are  available  in  the  machine-readable  output of the script (all
       prefixed with HTS ()):

       SPEC_MEM, SPEC_DSK, SPEC_CPU, SPEC_RQN, SPEC_DISK_TEMPLATE, SPEC_SPN
              These represent the specifications of the instance model used for  allocation  (the
              memory, disk, cpu, requested nodes, disk template, spindles).

       TSPEC_INI_MEM, TSPEC_INI_DSK, TSPEC_INI_CPU, ...
              Only  defined  when the tiered mode allocation is enabled, these are similar to the
              above specifications but show the initial starting spec for tiered allocation.

       CLUSTER_MEM, CLUSTER_DSK, CLUSTER_CPU, CLUSTER_NODES, CLUSTER_SPN
              These represent the total memory, disk, CPU count, total nodes, and total  spindles
              in the cluster.

       INI_SCORE, FIN_SCORE
              These  are the initial (current) and final cluster score (see the hbal man page for
              details about the scoring algorithm).

       INI_INST_CNT, FIN_INST_CNT
              The initial and final instance count.

       INI_MEM_FREE, FIN_MEM_FREE
              The initial  and  final  total  free  memory  in  the  cluster  (but  this  doesn't
              necessarily mean available for use).

       INI_MEM_AVAIL, FIN_MEM_AVAIL
              The  initial  and  final  total available memory for allocation in the cluster.  If
              allocating redundant instances, new instances could increase the reserved memory so
              it  doesn't  necessarily  mean  the  entirety  of  this  memory can be used for new
              instance allocations.

       INI_MEM_RESVD, FIN_MEM_RESVD
              The initial and final reserved memory (for redundancy/N+1 purposes).

       INI_MEM_INST, FIN_MEM_INST
              The initial and final memory used for instances (actual runtime used RAM).

       INI_MEM_OVERHEAD, FIN_MEM_OVERHEAD
              The initial and final memory overhead, i.e.  memory used for the  node  itself  and
              unaccounted memory (e.g.  due to hypervisor overhead).

       INI_MEM_EFF, HTS_INI_MEM_EFF
              The  initial and final memory efficiency, represented as instance memory divided by
              total memory.

       INI_DSK_FREE, INI_DSK_AVAIL, INI_DSK_RESVD, INI_DSK_INST, INI_DSK_EFF
              Initial disk stats, similar to the memory ones.

       FIN_DSK_FREE, FIN_DSK_AVAIL, FIN_DSK_RESVD, FIN_DSK_INST, FIN_DSK_EFF
              Final disk stats, similar to the memory ones.

       INI_SPN_FREE, ..., FIN_SPN_FREE, ..
              Initial and final spindles stats, similar to memory ones.

       INI_CPU_INST, FIN_CPU_INST
              Initial and final number of virtual CPUs used by instances.

       INI_CPU_EFF, FIN_CPU_EFF
              The initial and final CPU efficiency, represented as the count of virtual  instance
              CPUs divided by the total physical CPU count.

       INI_MNODE_MEM_AVAIL, FIN_MNODE_MEM_AVAIL
              The  initial  and final maximum per-node available memory.  This is not very useful
              as a metric but can give an impression of the status of the nodes; as  an  example,
              this  value  restricts  the  maximum instance size that can be still created on the
              cluster.

       INI_MNODE_DSK_AVAIL, FIN_MNODE_DSK_AVAIL
              Like the above but for disk.

       TSPEC  This parameter holds the pairs of specifications and counts of instances  that  can
              be   created   in  the  tiered  allocation  mode.   The  value  of  the  key  is  a
              space-separated   list    of    values;    each    value    is    of    the    form
              memory,disk,vcpu,spindles=count  where the memory, disk and vcpu are the values for
              the current spec, and count is how many instances of this spec can be  created.   A
              complete  value  for this variable could be: 4096,102400,2,1=225 2560,102400,2,1=20
              512,102400,2,1=21.

       KM_USED_CPU, KM_USED_NPU, KM_USED_MEM, KM_USED_DSK
              These represents the metrics of used resources at  the  start  of  the  computation
              (only  for  tiered allocation mode).  The NPU value is "normalized" CPU count, i.e.
              the number of virtual CPUs divided by the maximum ratio of the virtual to  physical
              CPUs.

       KM_POOL_CPU, KM_POOL_NPU, KM_POOL_MEM, KM_POOL_DSK
              These  represents  the  total  resources  allocated  during  the  tiered allocation
              process.  In effect, they represent how much is readily available for allocation.

       KM_UNAV_CPU, KM_POOL_NPU, KM_UNAV_MEM, KM_UNAV_DSK
              These represents the  resources  left  over  (either  free  as  in  unallocable  or
              allocable  on  their  own)  after  the  tiered allocation has been completed.  They
              represent better the actual unallocable resources, because some other resource  has
              been  exhausted.   For  example, the cluster might still have 100GiB disk free, but
              with no memory left for instances, we  cannot  allocate  another  instance,  so  in
              effect  the  disk space is unallocable.  Note that the CPUs here represent instance
              virtual CPUs, and in case the --max-cpu option hasn't been specified this  will  be
              -1.

       ALLOC_USAGE
              The  current  usage  represented  as  initial number of instances divided per final
              number of instances.

       ALLOC_COUNT
              The number of instances allocated (delta between FIN_INST_CNT and INI_INST_CNT).

       ALLOC_FAIL*_CNT
              For the last attemp at allocations (which would have  increased  FIN_INST_CNT  with
              one,  if  it  had  succeeded), this is the count of the failure reasons per failure
              type; currently defined are FAILMEM, FAILDISK and FAILCPU  which  represent  errors
              due  to  not  enough  memory,  disk and CPUs, and FAILN1 which represents a non N+1
              compliant cluster on which we can't allocate instances at all.

       ALLOC_FAIL_REASON
              The reason for most of the failures, being one of the above FAIL* strings.

       OK     A marker representing the successful end of the computation, and having value  "1".
              If  this  key is not present in the output it means that the computation failed and
              any values present should not be relied upon.

       Many of the INI_/FIN_ metrics will be also displayed with a TRL_ prefix,  and  denote  the
       cluster status at the end of the tiered allocation run.

       The human output format should be self-explanatory, so it is not described further.

OPTIONS

       The options that can be passed to the program are as follows:

       --disk-template template
              Overrides  the  disk  template  for  the instance read from the cluster; one of the
              Ganeti disk templates (e.g.  plain, drbd, so on) should be passed in.

       --spindle-use spindles
              Override the spindle use for the instance read from the cluster.  The value can  be
              0  (for example for instances that use very low I/O), but not negative.  For shared
              storage the value is ignored.

       --max-cpu=*cpu-ratio*
              The maximum virtual to physical cpu ratio, as a floating point number greater  than
              or  equal to one.  For example, specifying cpu-ratio as 2.5 means that, for a 4-cpu
              machine, a maximum of 10 virtual cpus should be allowed to be in  use  for  primary
              instances.   A value of exactly one means there will be no over-subscription of CPU
              (except for the CPU time used by the node itself), and values below one do not make
              sense,  as  that  means other resources (e.g.  disk) won't be fully utilised due to
              CPU restrictions.

       --min-disk=*disk-ratio*
              The minimum amount of free disk space remaining, as a floating point  number.   For
              example,  specifying  disk-ratio  as  0.25  means that at least one quarter of disk
              space should be left free on nodes.

       --independent-groups
              Consider all groups independent.  That is, if a node  that  is  not  N+1  happy  is
              found,  ignore its group, but still do allocation in the other groups.  The default
              is to not try allocation at all, if some not N+1 happy node is found.

       --accept-existing-errors
              This is a strengthened form of --independent-groups.  It tells hspace to ignore the
              presence  of  not  N+1  happy  nodes  and  just allocate on all other nodes without
              introducing new N+1 violations.  Note that this tends to overestimate the capacity,
              as instances still have to be moved away from the existing not N+1 happy nodes.

       --no-capacity-checks
              Normally, hspace will only consider those allocations where all instances of a node
              can immediately restarted should that node fail.  With this  option  given,  hspace
              will check only N+1 redundancy for DRBD instances.

       -l rounds, --max-length=*rounds*
              Restrict  the  number  of  instance  allocations  to this length.  This is not very
              useful in practice, but can be used for testing hspace  itself,  or  to  limit  the
              runtime for very big clusters.

       -p, --print-nodes
              Prints  the before and after node status, in a format designed to allow the user to
              understand the node's most important parameters.  See the man  page  htools(1)  for
              more details about this option.

       -O name
              This  option  (which can be given multiple times) will mark nodes as being offline.
              This means a couple of things:

              · instances won't be placed on these nodes, not even temporarily; e.g.  the replace
                primary  move  is not available if the secondary node is offline, since this move
                requires a failover.

              · these nodes will not be  included  in  the  score  calculation  (except  for  the
                percentage of instances on offline nodes)

              Note  that  the algorithm will also mark as offline any nodes which are reported by
              RAPI as such, or that have "?" in file-based input in any numeric fields.

       -S filename, --save-cluster=*filename*
              If given, the state of the cluster at the end of the allocation is saved to a  file
              named  filename.alloc,  and if tiered allocation is enabled, the state after tiered
              allocation will be saved to filename.tiered.  This allows  re-feeding  the  cluster
              state  to either hspace itself (with different parameters) or for example hbal, via
              the -t option.

       -t datafile, --text-data=*datafile*
              Backend specification: the name of the file holding node and  instance  information
              (if  not  collecting  via RAPI or LUXI).  This or one of the other backends must be
              selected.  The option is described in the man page htools(1).

       -m cluster
              Backend specification: collect data directly from the cluster given as an  argument
              via RAPI.  The option is described in the man page htools(1).

       -L [path]
              Backend specification: collect data directly from the master daemon, which is to be
              contacted via LUXI (an internal Ganeti protocol).  The option is described  in  the
              man page htools(1).

       --simulate description
              Backend specification: similar to the -t option, this allows overriding the cluster
              data with a simulated cluster.  For details about the description, see the man page
              htools(1).

       --standard-alloc disk,ram,cpu
              This  option  overrides  the  instance  size read from the cluster for the standard
              allocation mode, where we simply allocate instances of the same, fixed  size  until
              the cluster runs out of space.

              The specification given is similar to the --simulate option and it holds:

              · the disk size of the instance (units can be used)

              · the memory size of the instance (units can be used)

              · the vcpu count for the insance

              An  example  description would be 100G,4g,2 describing an instance specification of
              100GB of disk space, 4GiB of memory and 2 VCPUs.

       --tiered-alloc disk,ram,cpu
              This option overrides the instance size for the tiered allocation  mode.   In  this
              mode,  the  algorithm starts from the given specification and allocates until there
              is no more space; then it decreases the  specification  and  tries  the  allocation
              again.  The decrease is done on the metric that last failed during allocation.  The
              argument should have the same format as for --standard-alloc.

              Also note that the normal allocation and the tiered allocation are independent, and
              both  start  from  the initial cluster state; as such, the instance count for these
              two modes are not related one to another.

       --machine-readable[=*choice*]
              By default, the output of the program is in  "human-readable"  format,  i.e.   text
              descriptions.   By  passing  this flag you can either enable (--machine-readable or
              --machine-readable=yes) or explicitly disable (--machine-readable=no)  the  machine
              readable format described above.

       -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
       By  default, all 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.

EXIT STATUS

       The exist status of the command will be zero, unless for some reason the algorithm fatally
       failed (e.g.  wrong node or instance data).

BUGS

       The  algorithm is highly dependent on the number of nodes; its runtime grows exponentially
       with this number, and as such is impractical for really big clusters.

       The algorithm doesn't rebalance the cluster or  try  to  get  the  optimal  fit;  it  just
       allocates  in  the  best place for the current step, without taking into consideration the
       impact on future placements.

REPORTING BUGS

       Report  bugs  to  project  website  (http://code.google.com/p/ganeti/)  or   contact   the
       developers using the Ganeti mailing list (ganeti@googlegroups.com).

SEE ALSO

       Ganeti  overview  and specifications: ganeti(7) (general overview), ganeti-os-interface(7)
       (guest OS definitions), ganeti-extstorage-interface(7) (external storage providers).

       Ganeti  commands:  gnt-cluster(8)   (cluster-wide   commands),   gnt-job(8)   (job-related
       commands),  gnt-node(8)  (node-related  commands),  gnt-instance(8)  (instance  commands),
       gnt-os(8) (guest OS commands), gnt-storage(8) (storage commands), gnt-group(8) (node group
       commands), gnt-backup(8) (instance import/export commands), gnt-debug(8) (debug commands).

       Ganeti  daemons:  ganeti-watcher(8) (automatic instance restarter), ganeti-cleaner(8) (job
       queue cleaner), ganeti-noded(8) (node daemon), ganeti-rapi(8) (remote API daemon).

       Ganeti htools: htools(1) (generic binary), hbal(1) (cluster balancer), hspace(1) (capacity
       calculation),  hail(1) (IAllocator plugin), hscan(1) (data gatherer from remote clusters),
       hinfo(1) (cluster information printer), mon-collector(7) (data collectors interface).

COPYRIGHT

       Copyright (C) 2006-2015 Google Inc.  All rights reserved.

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       2.  Redistributions in binary form must reproduce the above copyright notice, this list of
       conditions  and  the  following  disclaimer  in  the  documentation and/or other materials
       provided with the distribution.

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