.TH HSPACE 1 2009-06-01 htools "Ganeti H-tools" .SH NAME hspace \- Cluster space analyzer for Ganeti .SH SYNOPSIS .B hspace .B "[backend options...]" .B "[algorithm options...]" .B "[request options..."] .BI "[ -p[" fields "] ]" .B "[-v... | -q]" .B hspace .B --version .TP Backend options: .BI " -m " cluster | .BI " -L[" path "]" | .BI " -n " nodes-file .BI " -i " instances-file | .BI " --simulate " spec .TP Algorithm options: .BI "[ --max-cpu " cpu-ratio " ]" .BI "[ --min-disk " disk-ratio " ]" .BI "[ -O " name... " ]" .TP Request options: .BI "[--memory " mem "]" .BI "[--disk " disk "]" .BI "[--req-nodes " req-nodes "]" .BI "[--vcpus " vcpus "]" .BI "[--tiered-alloc " spec "]" .SH 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. The output of the program is designed to interpreted as a shell fragment (or parsed as a \fIkey=value\fR file). Options which extend the output (e.g. -p, -v) will output the additional information on stderr (such that the stdout is still parseable). The following keys are available in the output of the script (all prefixed with \fIHTS_\fR): .TP .I SPEC_MEM, SPEC_DSK, SPEC_CPU, SPEC_RQN These represent the specifications of the instance model used for allocation (the memory, disk, cpu, requested nodes). .TP .I CLUSTER_MEM, CLUSTER_DSK, CLUSTER_CPU, CLUSTER_NODES These represent the total memory, disk, CPU count and total nodes in the cluster. .TP .I INI_SCORE, FIN_SCORE These are the initial (current) and final cluster score (see the hbal man page for details about the scoring algorithm). .TP .I INI_INST_CNT, FIN_INST_CNT The initial and final instance count. .TP .I 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). .TP .I 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. .TP .I INI_MEM_RESVD, FIN_MEM_RESVD The initial and final reserved memory (for redundancy/N+1 purposes). .TP .I INI_MEM_INST, FIN_MEM_INST The initial and final memory used for instances (actual runtime used RAM). .TP .I INI_MEM_OVERHEAD, FIN_MEM_OVERHEAD The initial and final memory overhead - memory used for the node itself and unacounted memory (e.g. due to hypervisor overhead). .TP .I INI_MEM_EFF, HTS_INI_MEM_EFF The initial and final memory efficiency, represented as instance memory divided by total memory. .TP .I INI_DSK_FREE, INI_DSK_AVAIL, INI_DSK_RESVD, INI_DSK_INST, INI_DSK_EFF Initial disk stats, similar to the memory ones. .TP .I FIN_DSK_FREE, FIN_DSK_AVAIL, FIN_DSK_RESVD, FIN_DSK_INST, FIN_DSK_EFF Final disk stats, similar to the memory ones. .TP .I INI_CPU_INST, FIN_CPU_INST Initial and final number of virtual CPUs used by instances. .TP .I 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. .TP .I 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. .TP .I INI_MNODE_DSK_AVAIL, FIN_MNODE_DSK_AVAIL Like the above but for disk. .TP .I TSPEC If the tiered allocation mode has been enabled, this parameter holds the pairs of specifications and counts of instances that can be created in this mode. The value of the key is a space-separated list of values; each value is of the form \fImemory,disk,vcpu=count\fR 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: \fB4096,102400,2=225 2560,102400,2=20 512,102400,2=21\fR. .TP .I ALLOC_USAGE The current usage represented as initial number of instances divided per final number of instances. .TP .I ALLOC_COUNT The number of instances allocated (delta between FIN_INST_CNT and INI_INST_CNT). .TP .I 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. .TP .I ALLOC_FAIL_REASON The reason for most of the failures, being one of the above FAIL* strings. .TP .I 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. .PP If the tiered allocation mode is enabled, then 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. .SH OPTIONS The options that can be passed to the program are as follows: .TP .BI "--memory " mem The memory size of the instances to be placed (defaults to 4GiB). .TP .BI "--disk " disk The disk size of the instances to be placed (defaults to 100GiB). .TP .BI "--req-nodes " num-nodes The number of nodes for the instances; the default of two means mirrored instances, while passing one means plain type instances. .TP .BI "--vcpus " vcpus The number of VCPUs of the instances to be placed (defaults to 1). .TP .BI "--max-cpu " cpu-ratio The maximum virtual-to-physical cpu ratio, as a floating point number between zero and one. For example, specifying \fIcpu-ratio\fR as \fB2.5\fR 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 one doesn't make sense though, as that means no disk space can be used on it. .TP .BI "--min-disk " disk-ratio The minimum amount of free disk space remaining, as a floating point number. For example, specifying \fIdisk-ratio\fR as \fB0.25\fR means that at least one quarter of disk space should be left free on nodes. .TP .B -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. 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). By default, the node list will contain these informations: .RS .TP .B F a character denoting the status of the node, with '-' meaning an offline node, '*' meaning N+1 failure and blank meaning a good node .TP .B Name the node name .TP .B t_mem the total node memory .TP .B n_mem the memory used by the node itself .TP .B i_mem the memory used by instances .TP .B 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 .TP .B f_mem the free node memory .TP .B r_mem the reserved node memory, which is the amount of free memory needed for N+1 compliance .TP .B t_dsk total disk .TP .B f_dsk free disk .TP .B pcpu the number of physical cpus on the node .TP .B vcpu the number of virtual cpus allocated to primary instances .TP .B pri number of primary instances .TP .B sec number of secondary instances .TP .B p_fmem percent of free memory .TP .B p_fdsk percent of free disk .TP .B r_cpu ratio of virtual to physical cpus .TP .B lCpu the dynamic CPU load (if the information is available) .TP .B lMem the dynamic memory load (if the information is available) .TP .B lDsk the dynamic disk load (if the information is available) .TP .B lNet the dynamic net load (if the information is available) .RE .TP .BI "-O " name This option (which can be given multiple times) will mark nodes as being \fIoffline\fR, and instances won't be placed on these nodes. Note that hspace 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. .RE .TP .BI "-n" nodefile ", --nodes=" nodefile The name of the file holding node information (if not collecting via RAPI), instead of the default \fInodes\fR file (but see below how to customize the default value via the environment). .TP .BI "-i" instancefile ", --instances=" instancefile The name of the file holding instance information (if not collecting via RAPI), instead of the default \fIinstances\fR file (but see below how to customize the default value via the environment). .TP .BI "-m" cluster Collect data not from files but directly from the .I cluster given as an argument via RAPI. If the argument doesn't contain a colon (:), then it is converted into a fully-built URL via prepending https:// and appending the default RAPI port, otherwise it's considered a fully-specified URL and is used as-is. .TP .BI "-L[" path "]" Collect data not from files but directly from the master daemon, which is to be contacted via the luxi (an internal Ganeti protocol). An optional \fIpath\fR argument is interpreted as the path to the unix socket on which the master daemon listens; otherwise, the default path used by ganeti when installed with "--localstatedir=/var" is used. .TP .BI "--simulate " description Instead of using actual data, build an empty cluster given a node description. The \fIdescription\fR parameter must be a comma-separated list of four elements, describing in order: .RS .RS .TP the number of nodes in the cluster .TP the disk size of the nodes, in mebibytes .TP the memory size of the nodes, in mebibytes .TP the cpu core count for the nodes .RE An example description would be \fB20,102400,16384,4\fR describing a 20-node cluster where each node has 100GiB of disk space, 16GiB of memory and 4 CPU cores. Note that all nodes must have the same specs currently. .RE .TP .BI "--tiered-alloc " spec Beside the standard, fixed-size allocation, also do a tiered allocation scheme where 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 matric that last failed during allocation. The specification given is similar to the "--simulate" option and it holds: .RS .RS .TP the disk size of the instance .TP the memory size of the instance .TP the vcpu count for the insance .RE An example description would be \fB10240,8192,2\fR describing an initial starting specification of 10GiB of disk space, 4GiB of memory and 2 VCPUs. 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. .RE .TP .B -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. At verbosity 2 the location of the new instances is shown in the standard error. .TP .B -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. .TP .B -V, --version Just show the program version and exit. .SH 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). .SH 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. .SH ENVIRONMENT If the variables \fBHTOOLS_NODES\fR and \fBHTOOLS_INSTANCES\fR are present in the environment, they will override the default names for the nodes and instances files. These will have of course no effect when the RAPI or Luxi backends are used. .SH SEE ALSO .BR hbal "(1), " hscan "(1), " ganeti "(7), " gnt-instance "(8), " .BR gnt-node "(8)" .SH "COPYRIGHT" .PP Copyright (C) 2009 Google Inc. Permission is granted to copy, distribute and/or modify under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. .PP On Debian systems, the complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL.