3. Using Stork¶
This section describes how to use the features available in
Stork, use a web browser and connect to port 8080. If
Stork is running on a localhost, it can be reached by navigating to
3.1. Managing Users¶
A default administrator account is created upon initial installation of Stork. It can be used to
sign in to the system via the web UI, using the username
admin and password
To manage users, click on the
Configuration menu and choose
Users to see a list of
existing users. There will be at least one user,
To add a new user, click
Create User Account. A new tab opens to
specify the new account parameters. Some fields have specific
- Username can consist of only letters, numbers, and an underscore (_).
- The e-mail field is optional, but if specified, it must be a well-formed e-mail.
- The firstname and lastname fields are mandatory.
- The password must only contain letters, digits, @, ., !, +, or -, and must be at least eight characters long.
Currently, users are associated with one of the two predefined groups
admin, which must be selected
when the user account is created. Users belonging to the
super-admin group are granted full privileges in the system,
including creation and management of user accounts. The
group has similar privileges, except that the users in this group are
not allowed to manage other users’ accounts.
Once the new user account information has been specified and all
requirements are met, the
Save button becomes active and the new
account can be enabled.
3.2. Changing a User Password¶
An initial password is assigned by the administrator when a user
account is created. Each user should change the password when first
logging into the system. To change the password, click on the
Profile menu and choose
Settings to display the user profile
information. Click on
Change password in the menu bar on the left
and specify the current password in the first input box. The new
password must be specified and confirmed in the second and third input
boxes, and must meet the password requirements specified in the
previous section. When all entered data is valid, the
is activated for changing the password.
3.3. Deploying Stork Agent¶
The Stork system uses agents to monitor services.
Stork Agent is a
daemon that must be deployed and run on each machine to be
monitored. Currently, there are no automated deployment routines and
Stork Agent must be installed manually. This can be done in one
of two ways: from RPM or deb packages (described in the
Installation chapter), or by simply copying the
binary to the destination machine manually. The packages are usually far
Assuming you choose to not use the packages, the Stork Agent binary can be copied manually. Assuming services will be monitored on a machine with the IP 192.0.2.1, enter the following on the Stork server command line:
$ cd <stork-dir> $ scp backend/cmd/stork-agent firstname.lastname@example.org:/path
On the machine to be monitored, start the agent by running:
It is possible to set the
environment variables to specify which address the agent listens
STORK_AGENT_PORT environment variables
specify which TCP port the agent listens on.
Normally, the agent will create a TCP socket on which to listen
for commmands from a stork-server and create exporters which
export data to Prometheus. There are two command line flags
which may be used to alter this behavior. The
flag instructs the agent to listen for commands from the Stork Server
but not for Prometheus requests. Conversely, the
--listen-prometheus-only flag instructs the agent to listen for
Prometheus requests but not for commands from the Stork Server.
Unless explicitly specified, the agent listens on all addresses on port 8080. There are no authentication mechanisms implemented in the agent yet. Use with care!
3.4. Connecting and Monitoring Machines¶
3.4.1. Registering a New Machine¶
Once the agent is deployed and running on the machine to be monitored,
Stork Server must be instructed to start monitoring it. This
can be done via the
Services menu, under
see a list of currently registered machines.
To add a new machine, click
Add New Machine and specify the
machine address (IP address, hostname, or FQDN) and a port.
Add button is clicked, the server attempts to establish
a connection to the agent. Make sure that any active firewalls will
allow incoming connections to the TCP port specified.
Once a machine is added, a number of parameters are displayed, including hostname, address, agent version, number of CPU cores, CPU load, available total memory, current memory utilization, uptime, OS, platform family, platform name, OS version, kernel, virtualization details (if any), and host ID.
If any applications, i.e. Kea DHCP and/or BIND 9, are detected on this machine, the status of those applications is displayed and the link allows navigation to the application details.
Navigation to the discovered applications is also possible through the
3.4.2. Monitoring a Machine¶
Monitoring of registered machines is accomplished via the Services menu, under Machines. A list of currently registered machines is displayed, with multiple pages available if needed.
A filtering mechanism that acts as an omnibox is available. Via a typed string, Stork can search for an address, agent version, hostname, OS, platform, OS version, kernel version, kernel architecture, virtualization system, or host-id fields.
The state of a machine can be inspected by clicking its hostname; a new tab opens with the machine’s details. Multiple tabs can be open at the same time, and clicking Refresh updates the available information.
The machine state can also be refreshed via the Action menu. On the Machines list, each machine has its own menu; click on the triple-lines button at the right side and choose the Refresh option.
3.4.3. Deleting a Machine¶
To stop monitoring a machine, go to the Machines list, find the
machine to stop monitoring, click on the triple-lines button at the
right side, and choose Delete. This will terminate the connection
between the Stork server and the agent running on the machine, and the
server will no longer monitor it. However, the Stork agent process
will continue running on the machine. Complete shutdown of a Stork
agent process must be done manually, e.g. by connecting to the machine
using ssh and stopping the agent there. One way to achieve that is to
killall stork-agent command.
3.5. Monitoring Applications¶
3.5.1. Application Status¶
Kea DHCP and BIND 9 applications discovered on connected machines are
listed via the top-level menu bar, under
Services. Both the Kea
and BIND 9 applications can be selected; the list view includes the
application version, application status, and some machine details. The
Action button is also available, to refresh the information about
The application status displays a list of daemons belonging to the
application. For BIND 9, it is always only one daemon,
the case of Kea, several daemons may be presented in the application
status column, typically: DHCPv4, DHCPv6, DDNS, and CA (Kea Control
For BIND 9, the Stork Agent is looking for the
named in the
process list and parses the configuration file that is given with
-c argument. If the
named process is started without a
specific configuration file, the Stork Agent will default to
rndc to retrieve the application status. It looks for
controls statement in the configuration file, and uses the
first listed control point for monitoring the application.
Furthermore, the Stork Agent can be used as a Prometheus exporter.
Stork is able to do so if
named is built with
it will gather statistics via the JSON statistics API. The
named.conf file must have a
statistics-channel configured and
the exporter will query the first listed channel. Stork is able to export the
most metrics if
zone-statistics is set to
full in the
For Kea, the listed daemons are those that Stork finds in the CA configuration file. A warning sign is displayed for any daemons from the CA configuration file that are not running. In cases when the Kea installation is simply using the default CA configuration file, which includes configuration of daemons that are never intended to be launched, it is recommended to remove (or comment out) those configurations to eliminate unwanted warnings from Stork about inactive daemons.
3.5.2. IPv4 and IPv6 Subnets per Kea Application¶
One of the primary configuration aspects of any network is the layout of IP addressing. This is represented in Kea with IPv4 and IPv6 subnets. Each subnet represents addresses used on a physical link. Typically, certain parts of each subnet (“pools”) are delegated to the DHCP server to manage. Stork is able to display this information.
One way to inspect the subnets and pools within Kea is by looking at each Kea application to get an overview of what configurations a specific Kea application is serving. A list of configured subnets on that specific Kea application is displayed. The following picture shows a simple view of the Kea DHCPv6 server running with a single subnet, with three pools configured in it.
3.5.3. IPv4 and IPv6 Subnets in the Whole Network¶
It is convenient to see the complete overview of all subnets configured in the network being monitored by Stork. Once at least one machine with the Kea application running is added to Stork, click on the DHCP menu and choose Subnets to see all available subnets. The view shows all IPv4 and IPv6 subnets with the address pools and links to the applications that are providing them. An example view of all subnets in the network is presented in the figure below.
There are filtering capabilities available in Stork; it is possible to choose whether to see IPv4 only, IPv6 only, or both. There is also an omnisearch box available where users can type a search string. Note that for strings of four characters or more, the filtering takes place automatically, while shorter strings require the user to hit Enter. For example, in the above situation it is possible to show only the first (192.0.2.0/24) subnet by searching for the 0.2 string. One can also search for specific pools, and easily filter the subnet with a specific pool, by searching for part of the pool ranges, e.g. 3.200.
Stork is able to display pool utilization for each subnet, and displays the absolute number of addresses allocated and percentage of usage. There are two thresholds: 80% (warning; the pool utilization bar becomes orange) and 90% (critical; the pool utilization bar becomes red).
As of Stork 0.5.0, if two or more servers are handling the same subnet (e.g. a HA pair), the same subnet is listed multiple times. This limitation will be addressed in future releases.
3.5.4. IPv4 and IPv6 Networks¶
Kea uses the concept of a shared network, which is essentially a stack of subnets deployed on the same physical link. Stork is able to retrieve information about shared networks and aggregate it across all configured Kea servers. The Shared Networks view allows for the inspection of networks and the subnets that belong in them. Pool utilization is shown for each subnet.
3.5.5. Host Reservations¶
Kea DHCP servers can be configured to assign static resources or parameters to the DHCP clients communicating with the servers. Most commonly these resources are the IP addresses or delegated prefixes. However, Kea also allows for assigning hostnames, PXE boot parameters, client classes, DHCP options, and others. The mechanism by which a given set of resources and/or parameters is associated with a given DHCP client is called “host reservations.”
A host reservation consists of one or more DHCP identifers used to associate the reservation with a client, e.g. MAC address, DUID, or client identifier; and a collection of resources and/or parameters to be returned to the client if the client’s DHCP message is associated with the host reservation by one of the identifiers. Stork can detect existing host reservations specified both in the configuration files of the monitored Kea servers and in the host database backends accessed via the Kea host_cmds premium hooks library. At present, Stork provides no means to update or delete host reservations.
All reservations detected by Stork can be listed by selecting the
menu option and then selecting
The first column in the presented view displays one or more DHCP identifiers
for each host in the format
hw-address is the identifier type. In this case, the identifier type is
the MAC address of the DHCP client for which the reservation has been specified.
Supported identifier types are described in the following sections of the Kea ARM:
Host Reservation in DHCPv4
and Host Reservation in DHCPv6.
If multiple identifiers are present for a reservation, the reservation will
be assigned when at least one of the identifiers matches the received DHCP packet.
The second column,
IP Reservations, includes the static assignments of the
IP addresses and/or delegated prefixes to the clients. There may be one or
more IP reservations for each host.
Hostname column contains an optional hostname reservation, i.e. the
hostname assigned to the particular client by the DHCP servers via the
Hostname or Client FQDN option.
Global/Subnet column contains the prefixes of the subnets to which the reserved
IP addresses and prefixes belong. If the reservation is global, i.e. is valid
for all configured subnets of the given server, the word “global” is shown
instead of the subnet prefix.
AppID @ Machine column includes one or more links to
Kea applications configured to assign each reservation to the
client. The number of applications will typically be greater than one
when Kea servers operate in the High Availability setup. In this case,
each of the HA peers uses the same configuration and may allocate IP
addresses and delegated prefixes to the same set of clients, including
static assignments via host reservations. If HA peers are configured
correctly, the reservations they share will have two links in
@ Machine column. Next to each link there is a little label indicating
whether the host reservation for the given server has been specified
in its configuration file or a host database (via host_cmds premium
Filter hosts input box is located above the Hosts table. It
allows for filtering the hosts by identifier types, identifier values, IP
reservations, hostnames and by globality i.e.
When filtering by DHCP identifier values, it is not necessary to use
colons between the pairs of hexadecimal digits. For example, the
hw-address=0a:1b:bd:43:5f:99 will be found regardless
of whether the filtering text is
3.5.6. Sources of Host Reservations¶
There are two ways to configure the Kea servers to use host reservations. First, the host reservations can be specified within the Kea configuration files; see Host Reservation in DHCPv4 for details. The other way is to use a host database backend, as described in Storing Host Reservations in MySQL, PostgreSQL, or Cassandra. The second solution requires the given Kea server to be configured to use the host_cmds premium hooks library. This library implements control commands used to store and fetch the host reservations from the host database which the Kea server is connected to. If the host_cmds hooks library is not loaded, Stork will only present the reservations specified within the Kea configuration files.
Stork periodically fetches the reservations from the host database backends and updates them in the local database. The default interval at which Stork refreshes host reservation information is set to 60 seconds. This means that an update in the host reservation database will not be visible in Stork until up to 60 seconds after it was applied. This interval is currently not configurable.
As of the Stork 0.7.0 release, the list of host reservations must be manually refreshed by reloading the browser page to observe the most recent updates fetched from the Kea servers.
3.5.7. Kea High Availability Status¶
When viewing the details of the Kea application for which High Availability is enabled (via the libdhcp_ha.so hooks library), the High Availability live status is presented and periodically refreshed for the DHCPv4 and/or DHCPv6 daemon configured as primary or secondary/standby server. The status is not displayed for the server configured as an HA backup. See the High Availability section in the Kea ARM for details about the roles of the servers within the HA setup.
The following picture shows a typical High Availability status view displayed in the Stork UI.
The local server is the DHCP server (daemon) belonging to the
application for which the status is displayed; the remote server is
its active HA partner. The remote server belongs to a different
application running on a different machine, and this machine may or
may not be monitored by Stork. The statuses of both the local and the
remote server are fetched by sending the status-get
command to the Kea server whose details are displayed (the local
server). In the load-balancing and hot-standby modes the local server
periodically checks the status of its partner by sending the
ha-heartbeat command to it. Therefore, this information is not
always up-to-date; its age depends on the heartbeat command interval
(typically 10 seconds). The status of the remote server includes the
age of the data displayed.
The status information contains the role, state, and scopes served by each HA partner. In the usual HA case, both servers are in load-balancing state, which means that both are serving DHCP clients and there is no failure. If the remote server crashes, the local server transitions to the partner-down state, which will be reflected in this view. If the local server crashes, this will manifest itself as a communication problem between Stork and the server.
As of Stork 0.8.0 release, the High Availability view may also contain the information about the heartbeat status between the two servers and the information about the failover progress. This information is only available while monitoring Kea 1.7.8 versions and later.
The failover progress information is only presented when one of the active servers has been unable to communicate with the partner via the heartbeat exchange for a time exceeding the max-heartbeat-delay threshold. If the server is configured to monitor the DHCP traffic directed to the partner to verify that the partner is not responding to this traffic before transitioning to the partner-down state, the information about the number of unacked clients (clients which failed to get the lease), connecting clients (all clients currently trying to get the lease from the partner) and the number of analyzed packets are displayed. The system administrator may use this information to diagnose why the failover transition has not taken place or when such transition is likely to happen.
More about High Availability status information provided by Kea can be found in the Kea ARM.
3.5.8. Viewing Kea Log¶
Stork offers a simple logs viewing mechanism to diagnose issues with monitored applications.
As of Kea 0.10 release, this mechanism only supports viewing Kea log files. Viewing BIND9 logs is not supported yet. Monitoring other logging locations such as: stdout, stderr or syslog is also not supported.
Kea can be configured to log into multiple destinations. Different types
of log messages may be output into different log files, syslog, stdout
or stderr. The list of log destinations used by the Kea application
is available on the Kea app page. Click on the Kea app whose logs you
want to view. Next, select the Kea daemon by clicking on one of the
DHCPv4 tab. Scroll down to the
This section contains a table with a list of configured loggers for the selected daemon. For each configured logger the logger’s name, logging severity and output location are presented. The possible output locations are: log file, stdout, stderr or syslog. It is only possible to view the logs output to the log files. Therefore, for each log file there is a link which leads to the log viewer showing the selected file’s contents. The loggers which output to the stdout, stderr and syslog are also listed but the links to the log viewer are not available for them.
Clicking on the selected log file navigates to the log viewer for this file. By default, the viewer displays the tail of the log file up to 4000 characters. Depending on the network latency and the size of the log file, it may take several seconds or more before the log contents are fetched and displayed.
The log viewer title bar comprises three buttons. The button with the refresh
icon triggers log data fetch without modifying the size of the presented
data. Clicking on the
+ button extends the size of the viewed log tail
by 4000 characters and refreshes the data in the log viewer. Conversely,
clicking on the
- button reduces the amount of presented data by
4000 characters. Every time any of these buttons is clicked, the viewer
discards currently presented data and displays the latest part of the
log file tail.
Please keep in mind that extending the size of the viewed log tail may cause slowness of the log viewer and network congestion as you increase the amount of data fetched from the monitored machine.
The Main Stork page presents a dashboard. It contains a panel with information about DHCP and a panel with events observed or noticed by Stork server.
3.6.1. DHCP Panel¶
DHCP panel includes two sections: one for DHCPv4 and one for DHCPv6. Each section contains 3 kinds of information:
- list of up to 5 subnets with the highest pool utilization
- list of up to 5 shared networks with the highest pool utilization
- statistics about DHCP
3.6.2. Events Panel¶
Events panel presents the list of the most recent events captured by the Stork server. There are 3 severity levels of the events: info, warning and error. Events pertaining to the particular entities, e.g. machines or applications, provide a link to a web page containing the information about the given object.