They can be installed in the OpenStack controller node or on another node.
Updating the Synergy packages
The Synergy project makes periodic releases. As a system administrator you can get the latest features and bug fixes by updating Synergy.
This is done using the standard update commands for your OS, as long you have the INDIGO repository set up.
On Ubuntu:
apt-get update
apt-get upgrade
On CentOS:
yum update
Once the update is complete remember to restart the service. Follow the instructions in "Configure and start Synergy" section of this guide to see how to do it.
Setup the Synergy database
Then use the database access client to connect to the database server as the root user:
$ mysql -u root -p
Create the synergy database:
CREATE DATABASE synergy;
Grant proper access to the glance database:
GRANT ALL PRIVILEGES ON
._ TO 'synergy'@'localhost' \
IDENTIFIED BY 'SYNERGY_DBPASS';
GRANT ALL PRIVILEGES ON synergy._ TO 'synergy'@'%' \
IDENTIFIED BY 'SYNERGY_DBPASS';
flush privileges;
Replace SYNERGY_DBPASS with a suitable password.
Exit the database access client.
Add Synergy as an OpenStack endpoint and service
Source the admin credentials to gain access to admin-only CLI commands:
$ . admin-openrc
Register the Synergy service and endpoint in the Openstack service catalog:
Make sure that nova notifications are enabled on the compute node. Edit the /etc/nova/nova.conf file. In the [DEFAULT] and [oslo_messaging_notifications] sections add the following attributes:
The topics parameter is used by Nova for informing listeners about the state changes of the VMs. In case some other service (e.g. Ceilometer) is listening on the default topic notifications, to avoid the competition on consuming the notifications, please define a new topic specific for Synergy (e.g. topics = notifications,synergy_notifications).
Configure Controller to use Synergy
In /etc/nova/ create a nova-conductor.conf file. Edit /etc/nova/nova-conductor.conf file and add the following to it:
[conductor]
topic=conductor_synergy
Perform these steps on the controller node.
Restart nova
Then restart the nova services on the Controller and Compute nodes.
Verify operation
Run this command on the controller node to check whether your configuration is correct:
please patch the the file /usr/lib/python2.7/site-packages/synergy_service-1.0.0-py2.7.egg-info/requires.txt by removing the versions after the dependencies.
The Synergy configuration file
Synergy must be configured properly filling the /etc/synergy/synergy.conf configuration file. To apply the changes of any configuration parameter, the Synergy service must be restarted.
This is an example of the synergy.conf configuration file:
[DEFAULT]
[Logger]
# set the logging file name
filename = /var/log/synergy/synergy.log
# set the logging level. Valid values are: CRITICAL, ERROR, WARNING, INFO, DEBUG, NOTSET.
level = INFO
# set the format of the logged messages
formatter = "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
# set the max file size
maxBytes = 1048576
# set the logging rotation threshold
backupCount = 100
[WSGI]
# set the Synergy hostname
host = SYNERGY_HOST
# set the WSGI port (default: 8051)
port = 8051
# set the number of threads
threads = 2
# set the SSL
use_ssl = False
#ssl_ca_file =
#ssl_cert_file =
#ssl_key_file =
max_header_line = 16384
retry_until_window = 30
tcp_keepidle = 600
backlog = 4096
[SchedulerManager]
autostart = True
# set the manager rate (minutes)
rate = 1
# set the list of projects accessing to the shared quota
# projects = prj_a, prj_b
#projects =
# set the projects share
# shares = prj_a=70, prj_b=30
#shares =
# set the default max time to live (minutes) for VM/Container (default: 2880)
default_TTL = 2880
# set, for the specified projects, the max time to live (minutes) for VM/Container
# TTLs = prj_a=1440, prj_b=2880
#TTLs =
# set the max depth used by the backfilling strategy (default: 100)
# this allows Synergy to not check the whole queue when looking for VMs to start
backfill_depth = 100
# set the notification topic used by Nova for informing listeners about the state
# changes of the VMs. In case some other service (e.g. Ceilometer) is listening
# on the default Nova topic (i.e. "notifications"), please define a new topic
specific for Synergy (e.g. notification_topics = notifications,synergy_notifications)
notification_topic = notifications
[FairShareManager]
autostart = True
# set the manager rate (minutes)
rate = 2
# set the period size (default: 7 days)
period_length = 7
# set num of periods (default: 3)
periods = 3
# set the default share value (default: 10)
default_share = 10
# set the dacay weight, float value [0,1] (default: 0.5)
decay_weight = 0.5
# set the vcpus weight (default: 100)
vcpus_weight = 50
# set the age weight (default: 10)
age_weight = 10
# set the memory weight (default: 70)
memory_weight = 70
[KeystoneManager]
autostart = True
# set the manager rate (minutes)
rate = 5
# set the Keystone url (v3 only)
auth_url = http://CONTROLLER_HOST:5000/v3
# set the name of user with admin role
#username =
# set the password of user with admin role
#password =
# set the project name to request authorization on
#project_name =
# set the project id to request authorization on
#project_id =
# set the http connection timeout (default: 60)
timeout = 60
# set the user domain name (default: default)
user_domain_name = default
# set the project domain name (default: default)
project_domain_name = default
# set the clock skew. This forces the request for token, a
# delta time before the token expiration (default: 60 sec)
clock_skew = 60
# set the PEM encoded Certificate Authority to use when verifying HTTPs connections
#ssl_ca_file =
# set the SSL client certificate (PEM encoded)
#ssl_cert_file =
[NovaManager]
autostart = True
# set the manager rate (minutes)
rate = 5
#set the http connection timeout (default: 60)
timeout = 60
# set the AMQP backend type (e.g. rabbit, qpid)
#amqp_backend =
# set the AMQP HA cluster host:port pairs
#amqp_hosts =
# set the AMQP broker address where a single node is used (default: localhost)
amqp_host = localhost
# set the AMQP broker port where a single node is used
amqp_port = 5672
# set the AMQP user
#amqp_user =
# set the AMQP user password
#amqp_password =
# set the AMQP virtual host (default: /)
amqp_virtual_host = /
# set the Nova host (default: localhost)
host = CONTROLLER_HOST
# set the Nova conductor topic (default: conductor)
conductor_topic = conductor
# set the Nova compute topic (default: compute)
compute_topic = compute
# set the Nova scheduler topic (default: scheduler)
scheduler_topic = scheduler
# set the Nova database connection
db_connection=DIALECT+DRIVER://USER:PASSWORD@DB_HOST/nova
# set the Nova CPU allocation ratio (default: 16)
cpu_allocation_ratio = 16
# set the Nova RAM allocation ratio (default: 1.5)
ram_allocation_ratio = 1.5
# set the Nova metadata_proxy_shared_secret
metadata_proxy_shared_secret =
# set the PEM encoded Certificate Authority to use when verifying HTTPs connections
#ssl_ca_file =
# set the SSL client certificate (PEM encoded)
#ssl_cert_file =
[QueueManager]
autostart = True
# set the manager rate (minutes)
rate = 60
# set the Synergy database connection:
db_connection = DIALECT+DRIVER://USER:PASSWORD@DB_HOST/synergy
# set the connection pool size (default: 10)
db_pool_size = 10
# set the number of seconds after which a connection is automatically
# recycled (default: 30)
db_pool_recycle = 30
# set the max overflow (default: 5)
db_max_overflow = 5
[QuotaManager]
autostart = True
# set the manager rate (minutes)
rate = 5
The following describes the meaning of the attributes of the Synergy configuration file, for each possible section:
The maximum size of a log file. When this size is reached, the log file is rotated
backupCount
The number of log files to be kept
Section [WSGI]
Attribute
Description
host
The hostname where the Synergy service is deployed
port
The port used by the Synergy service
threads
The number of threads used by the Synergy service
use ssl
Specify if the service is secured through SSL
ssl_ca_file
The CA certificate file to use to verify connecting clients
ssl_cert_file
The Identifying certificate PEM file to present to clients
ssl_key_file
The Private key PEM file used to sign cert_file certificate
max_header_line
The maximum size of message headers to be accepted (default: 16384)
retry_until_window
The number of seconds to keep retrying for listening (default: 30sec)
tcp_keepidle
The value of TCP_KEEPIDLE in seconds for each server socket
backlog
The number of backlog requests to configure the socket with (default: 4096). The listen backlog is a socket setting specifying that the kernel how to limit the number of outstanding (i.e. not yet accepted) connections in the listen queue of a listening socket. If the number of pending connections exceeds the specified size, new ones are automatically rejected
Section [SchedulerManager]
Attribute
Description
autostart
Specifies if the SchedulerManager manager should be started when Synergy starts
rate
the time (in minutes) between two executions of the task implementing this manager
projects
Defines the list of OpenStack projects entitled to access the dynamic resources
shares
Defines, for each project entitled to access the dynamic resources, the relevant share for the usage of such resources. If for a project the value is not specified, the value set for the attribute default_share in the FairShareManager section is used
default_TTL
Specifies the default maximum Time to Live for a Virtual Machine/container, in minutes (default: 2880)
TTLs
For each project, specifies the maximum Time to Live for a Virtual Machine/container, in minutes. VMs and containers running for more that this value will be killed by Synergy. If for a certain project the value is not specified, the value specified by the default_TTL attribute will be used
backfill_depth
The integer value expresses the max depth used by the backfilling strategy: this allows Synergy to not check the whole queue when looking for VMs to start (default: 100)
notification_topic
The notification topic used by Nova for informing listeners about the state changes of the VMs. In case some other service (e.g. Ceilometer) is listening on the default Nova topic (i.e. "notifications"), please define a new topic specific for Synergy (e.g. notification_topics = notifications,synergy_notifications)
Section [FairShareManager]
Attribute
Description
autostart
Specifies if the FairShare manager should be started when Synergy starts
rate
The time (in minutes) between two executions of the task implementing this manager
period_length
The time window considered for resource usage by the fair-share algorithm used by Synergy is split in periods having all the same length, and the most recent periods are given a higher weight. This attribute specifies the length, in days, of a single period (default: 7)
periods
The time window considered for resource usage by the fairshare algoritm used by Synergy is split in periods having all the same length, and the most recent periods are given a higher weight. This attribue specifies the number of periods to be considered (default: 3)
default_share
Specifies the default to be used for a project, if not specified in the shares attribute of the SchedulerManager section (default: 10)
decay_weight
Value between 0 and 1, used by the fairshare scheduler, to define how oldest periods should be given a less weight wrt resource usage (default: 0.5)
vcpus_weight
The weight to be used for the attribute concerning vcpus usage in the fairshare algorithm used by Synergy (default: 100)
age_weight
This attribute defines how oldest requests (and therefore with low priority) should have their priority increased so thay cam be eventaully served (default: 10)
memory_weight
The weight to be used for the attribute concerning memory usage in the fairshare algorithm used by Synergy (default: 70)
Section [KeystoneManager]
Attribute
Description
autostart
Specifies if the Keystone manager should be started when Synergy starts
rate
The time (in minutes) between two executions of the task implementing this manage
auth_url
The URL of the OpenStack identity service. Please note that the v3 API endpoint must be used
username
The name of the user with admin role
password
The password of the specified user with admin role
project_id
The project id to request authorization on
project_name
The project name to request authorization on
user_domain_name
The user domain name (default: "default")
project_domain_name
The project domain name (default: "default")
timeout
The http connection timeout (default: 60)
clock_skew
Forces the request for token, a delta time before the token expiration (default: 60 sec)
Section [NovaManager]
Attribute
Description
autostart
Specifies if the nova manager should be started when Synergy starts
rate
The time (in minutes) between two executions of the task implementing this manager
host
The hostname where the nova-conductor service runs (default: localhost)
timeout
The http connection timeout (default: 60)
amqp_backend
The AMQP backend tpye (rabbit or qpid)
amqp_hosts
The AMQP HA cluster host:port pairs
amqp_host
The server where the AMQP service runs (default: localhost)
amqp_port
The port used by the AMQP service
amqp_user
The AMQP userid
amqp_password
The password of the AMQP user
amqp_virtual_host
The AMQP virtual host
conductor_topic
The topic on which conductor nodes listen on (default: conductor)
compute_topic
The topic on which compute nodes listen on (default: compute)
scheduler_topic
The topic on which scheduler nodes listen on (default: scheduler)
cpu_allocation_ratio
The Nova CPU allocation ratio (default: 16)
ram_allocation_ratio
The Nova RAM allocation ratio (default: 1.5)
metadata_proxy_shared_secret
The Nova metadata_proxy_shared_secret
db_connection
The SQLAlchemy connection string to use to connect to the Nova database
Section [QueueManager]
Attribute
Description
autostart
Specifies if the Queue manager should be started when Synergy starts
rate
The time (in minutes) between two executions of the task implementing this manager
db_connection
The SQLAlchemy connection string to use to connect to the Synergy database
db_pool_size
The number of SQL connections to be kept open (default: 10)
db_pool_recycle
The number of seconds after which a connection is automatically recycled (default: 30)
db_max_overflow
The max overflow with SQLAlchemy (default: 5)
Section [QuotaManager]
Attribute
Description
autostart
Specifies if the Quota manager should be started when Synergy starts
rate
The time (in minutes) between two executions of the task implementing this manager
Installation and configuration using puppet
We provide a Puppet module for Synergy so users can install and configure Synergy with Puppet.
The module provides both the synergy-service and synergy-scheduler-manager components.
The Synergy service provides a command-line client, called synergy, which allows the Cloud administrator to control and monitor the Synergy service.
Before running the Synergy client command, you must create and source the admin-openrc.sh file to set the relevant environment variables. This is the same script used to run the OpenStack command line tools.
Note that the OS_AUTH_URL variables must refer to the v3 version of the keystone API, e.g.:
usage: synergy [-h] [--version] [--debug] [--os-username <auth-user-name>]
[--os-password <auth-password>]
[--os-user-domain-id <auth-user-domain-id>]
[--os-user-domain-name <auth-user-domain-name>]
[--os-project-name <auth-project-name>]
[--os-project-id <auth-project-id>]
[--os-project-domain-id <auth-project-domain-id>]
[--os-project-domain-name <auth-project-domain-name>]
[--os-auth-token <auth-token>] [--os-auth-token-cache]
[--os-auth-url <auth-url>] [--os-auth-system <auth-system>]
[--bypass-url <bypass-url>] [--os-cacert <ca-certificate>]
{manager,queue,quota,usage} ...
positional arguments:
{manager,queue,quota,usage}
commands
optional arguments:
-h, --help show this help message and exit
--version show program's version number and exit
--debug print debugging output
--os-username <auth-user-name>
defaults to env[OS_USERNAME]
--os-password <auth-password>
defaults to env[OS_PASSWORD]
--os-user-domain-id <auth-user-domain-id>
defaults to env[OS_USER_DOMAIN_ID]
--os-user-domain-name <auth-user-domain-name>
defaults to env[OS_USER_DOMAIN_NAME]
--os-project-name <auth-project-name>
defaults to env[OS_PROJECT_NAME]
--os-project-id <auth-project-id>
defaults to env[OS_PROJECT_ID]
--os-project-domain-id <auth-project-domain-id>
defaults to env[OS_PROJECT_DOMAIN_ID]
--os-project-domain-name <auth-project-domain-name>
defaults to env[OS_PROJECT_DOMAIN_NAME]
--os-auth-token <auth-token>
defaults to env[OS_AUTH_TOKEN]
--os-auth-token-cache
Use the auth token cache. Defaults to False if
env[OS_AUTH_TOKEN_CACHE] is not set
--os-auth-url <auth-url>
defaults to env[OS_AUTH_URL]
--os-auth-system <auth-system>
defaults to env[OS_AUTH_SYSTEM]
--bypass-url <bypass-url>
use this API endpoint instead of the Service Catalog
--os-cacert <ca-certificate>
Specify a CA bundle file to use in verifying a TLS
(https) server certificate. Defaults to env[OS_CACERT]
Command-line interface to the OpenStack Synergy API.
The synergy optional arguments:
-h, --help
Show help message and exit
--version
Show program’s version number and exit
--debug
Show debugging information
--os-username <auth-user-name>
Username to login with. Defaults to env[OS_USERNAME]
--os-password <auth-password>
Password to use.Defaults to env[OS_PASSWORD]
--os-project-name <auth-project-name>
Project name to scope to. Defaults to env:[OS_PROJECT_NAME]
--os-project-id <auth-project-id>
Id of the project to scope to. Defaults to env[OS_PROJECT_ID]
--os-project-domain-id <auth-project-domain-id>
Specify the project domain id. Defaults to env[OS_PROJECT_DOMAIN_ID]
Specify the project domain name. Defaults to env[OS_PROJECT_DOMAIN_NAME]
--os-user-domain-id <auth-user-domain-id>
Specify the user domain id. Defaults to env[OS_USER_DOMAIN_ID]
--os-user-domain-name <auth-user-domain-name>
Specify the user domain name. Defaults to env[OS_USER_DOMAIN_NAME]
--os-auth-token <auth-token>
The auth token to be used. Defaults to env[OS_AUTH_TOKEN]
--os-auth-token-cache
Use the auth token cache. Defaults to env[OS_AUTH_TOKEN_CACHE]to False.
Defaults to 'false' if not set
--os-auth-url <auth-url>
The URL of the Identity endpoint. Defaults to env[OS_AUTH_URL]
--os-auth-system <auth-system>
The auth system to be used. Defaults to env[OS_AUTH_SYSTEM]
--bypass-url <bypass-url>
Use this API endpoint instead of the Service Catalog
--os-cacert <ca-bundle-file>
Specify a CA certificate bundle file to use in verifying a TLS
(https) server certificate. Defaults to env[OS_CACERT]
synergy manager
This command allows to get information about the managers deployed in the Synergy service and control their execution:
# synergy manager -h
usage: synergy manager [-h] {list,status,start,stop} ...
positional arguments:
{list,status,start,stop}
list list the managers
status show the managers status
start start the manager
stop stop the manager
optional arguments:
-h, --help show this help message and exit
The command synergy manager list provides the list of all managers deployed in the Synergy service:
private quota: composed of resources statically allocated and managed using the 'standard' OpenStack policies
shared quota: composed of resources non statically allocated and fairly distributed among users by Synergy
The size of the shared quota is calculated as the difference between the total amount of cloud resources (considering also the over-commitment ratios) and the total resources allocated to the private quotas. Therefore for all projects it is necessary to specify the proper quota for instances, VCPUs and RAM so that their total is less than the total amount of cloud resources.
Since Synergy is installed, the private quota of projects cannot be managed anymore by using the Horizon dashboard, but only via command line tools using the following OpenStack command:
The private quota will be updated from Synergy after a few minutes without restart it. This example shows how the private quota of the project _prj_a (id=_a5ccbaf2a9da407484de2af881198eb9) has been modified:
# synergy quota show --project_name prj_a
╒═══════════╤═══════════════════════════════════════════════╤═════════════════════════════════════════════════════════════════════════════╕
│ project │ private quota │ shared quota │
╞═══════════╪═══════════════════════════════════════════════╪═════════════════════════════════════════════════════════════════════════════╡
│ prj_a │ vcpus: 0.00 of 3.00 | memory: 0.00 of 1024.00 │ vcpus: 0.00 of 26.00 | memory: 0.00 of 59956.00 | share: 70.00% | TTL: 5.00 │
╘═══════════╧═══════════════════════════════════════════════╧═════════════════════════════════════════════════════════════════════════════╛
# openstack quota set --cores 2 --ram 2048 --instances 10 --class a5ccbaf2a9da407484de2af881198eb9
# synergy quota show --project_name prj_a
╒═══════════╤═══════════════════════════════════════════════╤═════════════════════════════════════════════════════════════════════════════╕
│ project │ private quota │ shared quota │
╞═══════════╪═══════════════════════════════════════════════╪═════════════════════════════════════════════════════════════════════════════╡
│ prj_a │ vcpus: 0.00 of 2.00 | memory: 0.00 of 2048.00 │ vcpus: 0.00 of 27.00 | memory: 0.00 of 58932.00 | share: 70.00% | TTL: 5.00 │
╘═══════════╧═══════════════════════════════════════════════╧═════════════════════════════════════════════════════════════════════════════╛
To get information about the private and shared quotas you must use the synergy quota command :
# synergy quota -h
usage: synergy quota [-h] {show} ...
positional arguments:
{show}
show shows the quota info
optional arguments:
-h, --help show this help message and exit
# synergy quota show -h
usage: synergy quota show [-h] [-i <id> | -n <name> | -a | -s]
optional arguments:
-h, --help show this help message and exit
-i <id>, --project_id <id>
-n <name>, --project_name <name>
-a, --all_projects
-s, --shared
To get the status about the shared quota, use the option --shared:
in this example the total amount of VCPUs allocated to the shared quota is 27 whereof have been used just 2 CPUs (similarly to the memory and instances number). The value -1 means that the Cloud administrator has not fixed the limit of the number of instances (i.e. VMs), so in this example the VMs can be unlimited.
The --all_projects option provides information about the private and shared quotas of all projects:
# synergy quota show --all_projects
╒═══════════╤════════════════════════════════════════════════╤═══════════════════════════════════════════════════════════════════════════════╕
│ project │ private quota │ shared quota │
╞═══════════╪════════════════════════════════════════════════╪═══════════════════════════════════════════════════════════════════════════════╡
│ prj_b │ vcpus: 1.00 of 3.00 | memory: 512.0 of 1536.00 │ vcpus: 0.00 of 27.00 | memory: 0.00 of 60980.00 | share: 30.00% | TTL: 5.00 │
├───────────┼────────────────────────────────────────────────┼───────────────────────────────────────────────────────────────────────────────┤
│ prj_a │ vcpus: 0.00 of 1.00 | memory: 0.00 of 512.00 │ vcpus: 2.00 of 27.00 | memory: 1024.0 of 60980.00 | share: 70.00% | TTL: 5.00 │
╘═══════════╧════════════════════════════════════════════════╧═══════════════════════════════════════════════════════════════════════════════╛
# synergy quota show --project_name prj_a
╒═══════════╤══════════════════════════════════════════════╤═══════════════════════════════════════════════════════════════════════════════╕
│ project │ private quota │ shared quota │
╞═══════════╪══════════════════════════════════════════════╪═══════════════════════════════════════════════════════════════════════════════╡
│ prj_a │ vcpus: 0.00 of 1.00 | memory: 0.00 of 512.00 │ vcpus: 2.00 of 27.00 | memory: 1024.0 of 60980.00 | share: 70.00% | TTL: 5.00 │
╘═══════════╧══════════════════════════════════════════════╧═══════════════════════════════════════════════════════════════════════════════╛
In this example the project prj_b is currently consuming just resources of its private quota (1 VCPU and 512MB of memory) while the shared quota is not used. By contrary, the prj_a is consuming just the shared quota (2 VCPUs and 1024MB of memory). The share values fixed by the Cloud administrator are 70% for prj_a and 30% prj_b (the attribute shares in synergy.conf) while for both projects the TTL has been set to 5 minutes (the TTL attribute). Remark, in this example, the VMs instantiated in the shared quota can live just 5 minutes while the ones created in the private quota can live forever.
synergy queue
This command provides information about the amount of user requests stored in the persistent priority queue:
# synergy queue -h
usage: synergy queue [-h] {show} ...
positional arguments:
{show}
show shows the queue info
optional arguments:
-h, --help show this help message and exit
# synergy queue show
╒═════════╤════════╤═══════════╕
│ name │ size │ is open │
╞═════════╪════════╪═══════════╡
│ DYNAMIC │ 544 │ true │
╘═════════╧════════╧═══════════╛
synergy usage
To get information about the usage of shared resources at project or user level, use:
# synergy usage show -h
usage: synergy usage show [-h] {project,user} ...
positional arguments:
{project,user}
project project help
user user help
optional arguments:
-h, --help show this help message and exit
# synergy usage show project -h
usage: synergy usage show project [-h] [-d <id> | -m <name> | -a]
optional arguments:
-h, --help show this help message and exit
-d <id>, --project_id <id>
-m <name>, --project_name <name>
-a, --all_projects
# synergy usage show user -h
usage: synergy usage show user [-h] (-d <id> | -m <name>)
(-i <id> | -n <name> | -a)
optional arguments:
-h, --help show this help message and exit
-d <id>, --project_id <id>
-m <name>, --project_name <name>
-i <id>, --user_id <id>
-n <name>, --user_name <name>
-a, --all_users
The project sub-command provides the resource usage information by the projects.
The following example shows the projects prj_a (share: 70%) and prj_b (share: 30%) have consumed in the last three days, respectively 70.40% and 29.40% of shared resources:
The time window is defined by Cloud administrator by setting the attributes period and period_length in synergy.conf.
It may happen that the prj_a (or prj_b) doesn't have the need to consume shared resources for a while: in this scenario the others projects (i.e. prj_b) can take advantage and so consume more resources than the fixed share (i.e. 30%):
However, as soon as the prj_a requires more shared resources, it will gain a higher priority than the prj_b, in order to balance their usage.
The user sub-command provides the resource usage information by the project users.
The following example shows the usage report of users belonging to the project prj_a. They have the same value for share (35%) but different priority (user_a1=80, user_a2=100) because the user_a1 has consumed too much with respect to user_a2 (51.90% VS 48.10%).
To interact with Synergy using the client tool, just one port needs to be open.
This is the port defined in the Synergy configuration file (attribute port in the [WSGI] section). The default value is 8051.
