3. Using Stork

This section describes how to use the features available in Stork. To connect to Stork, use a web browser and connect to port 8080 on the Stork server machine. If stork-server is running on a localhost, it can be reached by navigating to http://localhost:8080.

3.1. Managing Users

A default administrator account is created when Stork is initially installed. It can be used to sign in to the system via the web UI, with the username admin and password admin.

To see a list of existing users, click on the Configuration menu and choose Users. There will be at least one user, admin.

To add a new user, click Create User Account. A new tab opens to specify the new account parameters. Some fields have specific restrictions:

• The 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 address.

• The firstname and lastname fields are mandatory for the user accounts managed by Stork. They are optional for authentication methods provided by hooks.

• The password must only contain letters, digits, @, ., !, +, or -, and must be at least eight characters long.

Currently, each user is associated with one of the two predefined groups (roles), which are super-admin or admin; one of these must be selected when a user account is created. Both types of users can view Stork status screens, edit interval and reporting configuration settings, and add/remove machines for monitoring. super-admin users can also create and manage user 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 their 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 entered 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 Save button is activated to change the password.

3.3. Configuration Settings

It is possible to control some of the Stork configuration settings from the web interface. Click on the Configuration menu and choose Settings. There are three classes of settings available: Security, Intervals and Grafana & Prometheus.

Security settings currently contain only one option, controlling whether or not the machines registration REST API endpoint is enabled. New machines connect to this endpoint when they begin the registration. In order to avoid malicious attempts to register fake machines in the Stork server it is practical to uncheck the Enable machine registration option when no new registrations are expected. The option can be re-enabled at any time when new registrations are required. Unchecking the option does not affect the ability to re-register the existing machines.

Intervals settings specify the configuration of “pullers.” A puller is a mechanism in Stork which triggers a specific action at the specified interval. Each puller has its own specific action and interval. The puller interval is specified in seconds and designates a time period between the completion of the previously invoked action and the beginning of the next invocation of this action. For example, if the Kea Hosts Puller Interval is set to 10 seconds and it takes five seconds to pull the hosts information, the time period between the starts of the two consecutive attempts to pull the hosts information is 15 seconds.

The pull time varies between deployments and depends on the amount of information pulled, network congestion, and other factors. The interval setting guarantees that there is a constant idle time between any consecutive attempts.

The Grafana & Prometheus settings currently allow the URLs of the Prometheus and Grafana instances used with Stork to be specified.

3.4. Connecting and Monitoring Machines

3.4.1. 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 field.

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.

3.4.2. Disconnecting From 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 terminates the connection between the Stork server and the agent running on the machine, and the server will no longer monitor that machine; however, the stork-agent process will continue running. 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. For example, when the Stork Agent has been installed from packages, run:

$ sudo systemctl stop isc-stork-agent

Alternatively:

$ sudo killall -9 stork-agent

3.4.3. Dumping Diagnostic Information Into a File

It is sometimes difficult or impossible to diagnose issues without seeing the actual logs, database contents, and configuration files. Gathering such information can be challenging for a user because it requires looking into many places like databases, remote machine logs, etc.

Stork makes it convenient for users to gather diagnostic information from the selected machines with a single click. Navigate to the Machines page (i.e., the page where all monitored machines are listed), click on the Action button for the selected machine, and choose the Dump Troubleshooting Data option. Alternatively, navigate to the selected machine’s page and click on the Dump Troubleshooting Data button at the bottom of the page. In both cases, the Stork server will automatically gather useful diagnostics information and offer it for download as a tar.gz file. The downloaded package contains configurations, log tails, stork-server settings, warning and error-level events, high availability services’ states etc.

Note

Stork sanitizes passwords and other sensitive information when it creates the package.

The tarball can be easily sent via email or attached to a bug report.

3.4.4. Communication Status with the Monitored Machines

The communication status with the monitored agents and daemons is shown on the apps pages for the respective daemons. To see the detailed status for all apps and daemons on a single page, navigate to Monitoring and then Communication. If this page shows no communication issues it means that all connected systems are online. Otherwise, it lists the hierarchical view of the Stork Agents, Kea Control Agents, and the daemons, highlighting the ones for which communication failures have occurred. The communication failures may be caused by a process failure (e.g., Stork Agent failure) or a machine failure. In the former case, it is possible that the other daemons are still running, but it is not guaranteed because of the lack of connectivity with these daemons via the failing agent. In the latter case, all processes on the culprit machine are down. Stork server tries to provide accurate data about the states of all the processes but it should be treated with caution.

3.5. Monitoring Applications

3.5.1. Application Status

Kea DHCP applications discovered on connected machines are listed via the top-level menu bar, under Services. 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.

The application status displays a list of daemons belonging to the application. Several daemons may be presented in the application status columns; typically, they include: DHCPv4, DHCPv6, DDNS, and Kea Control Agent (CA).

Stork uses rndc to retrieve the application’s status. It looks for the 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 if named is built with json-c, because it gathers statistics via the JSON statistics API. The named.conf file must have statistics-channel configured; the exporter queries the first listed channel. Stork is able to export the most metrics if zone-statistics is set to full in the named.conf configuration.

For Kea, the listed daemons are those that Stork finds in the Control Agent (CA) configuration file. A warning sign is displayed for any daemons from the CA configuration file that are not running. 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. Friendly App Names

Every app connected to Stork is assigned a default name. For example, if a Kea app runs on the machine abc.example.org, this app’s default name is kea@abc.example.org. Similarly, if a BIND 9 app runs on the machine with the address 192.0.2.3, the resulting app name is bind9@192.0.2.3. If multiple apps of a given type run on the same machine, a postfix with a unique identifier is appended to the duplicated names, e.g. bind9@192.0.2.3%56.

The default app names are unique so that the user can distinguish them in the dashboard, apps list, events panel, and other views. However, the default names may become lengthy when machines names consist of fully qualified domain names. When machines’ IP addresses are used instead of FQDNs, the app names are less meaningful for someone not familiar with addressing in the managed network. In these cases, users may prefer replacing the default app names with more descriptive ones.

Suppose there are two DHCP servers in the network, one on the first floor of a building and one on the second floor. A user may assign the names Floor 1 DHCP and Floor 2 DHCP to the respective DHCP servers in this case. The new names need not have the same pattern as the default names and may contain whitespace. The @ character is not required, but if it is present, the part of the name following this character (and before an optional % character) must be an address or name of the machine monitored in Stork. The following names: dhcp-server@floor1%123 and dhcp-server@floor1, are invalid unless floor1 is a monitored machine’s name. The special notation using two consecutive @ characters can be used to suppress this check. The dhcp-server@@floor1 is a valid name even if floor1 is not a machine’s name. In this case, floor1 can be a physical location of the DHCP server in a building.

To modify an app’s name, navigate to the selected app’s view. For example, select Services from the top menu bar and then click Kea Apps. Select an app from the presented apps list. Locate and click the pencil icon next to the app name in the app view. In the displayed dialog box, type the new app name. If the specified name is valid, the Rename button is enabled. Click this button to submit the new name. The Rename button is disabled if the name is invalid. In this case, a hint is displayed to explain the issues with the new name.

3.5.3. 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.

3.5.4. IPv4 and IPv6 Subnets in the Whole Network

It is convenient to see the complete overview of all subnets configured in the network that are 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.

Stork provides filtering capabilities; 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. 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 example 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 range, e.g. 3.200.

Stork displays pool utilization for each subnet, with the absolute number of addresses allocated and usage percentage. There are two thresholds: 80% (warning; the pool utilization bar turns orange) and 90% (critical; the pool utilization bar turns red).

3.5.5. 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 retrieves information about shared networks and aggregates it across all configured Kea servers. The Shared Networks view allows the inspection of networks and the subnets that belong in them. Pool utilization is shown for each subnet.

3.5.6. Host Reservations

3.5.6.1. Listing 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 assignment of hostnames, PXE boot parameters, client classes, DHCP options, and other parameters. 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 identifiers 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 Commands premium hook library.

All reservations detected by Stork can be listed by selecting the DHCP menu option and then selecting Host Reservations.

The first column in the presented view displays one or more DHCP identifiers for each host in the format hw-address=0a:1b:bd:43:5f:99, where 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 Administrator Reference Manual (ARM): Host Reservation in DHCPv4 and Host Reservation in DHCPv6.

The next two columns contain the static assignments of the IP addresses and/or delegated prefixes to the clients. There may be one or more such IP reservations for each host.

The 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.

The 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.

Finally, the App Name column includes one or more links to Kea applications configured to assign each reservation to the client. The number of applications is typically 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 the App Name column. Next to each link there is a label indicating whether the host reservation for the given server has been specified in its configuration file or a host database (via the Host Commands premium hook library).

The Filter hosts input box is located above the Hosts table. It allows the hosts to be filtered by identifier types, identifier values, IP reservations, and hostnames, and by globality, i.e., is:global and not:global. When filtering by DHCP identifier values, it is not necessary to use colons between the pairs of hexadecimal digits. For example, the reservation hw-address=0a:1b:bd:43:5f:99 will be found whether the filtering text is 1b:bd:43 or 1bbd43.

The filtering mechanism also recognizes a set of keywords that can be used in combination with integer values to search host reservations by selected properties. For example, type:

• appId:2 to search the host reservrations belonging to the app with ID 2.

• subnetId:78 to search the host reservations in subnet with ID 78. In this case the ID is the one assigned to the subnet by Stork.

• keaSubnetId:123 to search the host reservations in subnets with ID 123 assigned in the Kea configurations.

3.5.6.2. Host Reservation Usage Status

Clicking on a selected host in the host reservations list opens a new tab that shows host details. The tab also includes information about reserved addresses and delegated prefixes usage. Stork needs to query Kea servers to gather the lease information for each address and prefix in the selected reservation. It may take several seconds or longer before this information is available. The lease information can be refreshed using the Leases button at the bottom of the tab.

The usage status is shown next to each IP address and delegated prefix. Possible statuses and their meanings are listed in the table below.

Possible IP reservation statuses

Status	Meaning
in use	There are valid leases assigned to the client. The client owns the reservation, or the reservation includes the flex-id or circuit-id identifier, making it impossible to detect conflicts (see note below).
expired	At least one of the leases assigned to the client owning the reservation is expired.
declined	The address is declined on at least one of the Kea servers.
in conflict	At least one of the leases for the given reservation is assigned to a client that does not own this reservation.
unused	There are no leases for the given reservation.

View status details by expanding a selected address or delegated prefix row. Clicking on the selected address or delegated prefix navigates to the leases search page, where all leases associated with the address or prefix can be listed.

Note

Detecting in conflict status is currently not supported for host reservations with flex-id or circuit-id identifiers. If there are valid leases for such reservations, they are marked in use regardless of whether the conflict exists.

3.5.6.3. Sources of Host Reservations

There are two ways to configure 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 or PostgreSQL. The second solution requires the given Kea server to be configured to use the host_cmds premium hook library. This library implements control commands used to store and fetch the host reservations from the host database to which the Kea server is connected. If the host_cmds hook library is not loaded, Stork only presents 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 is not visible in Stork until up to 60 seconds after it was applied. This interval is configurable in the Stork interface.

Note

The list of host reservations must be manually refreshed by reloading the browser page to see the most recent updates fetched from the Kea servers.

3.5.6.4. Creating Host Reservations

Above the list of the host reservations, there is the New Host button that opens a tab where you can specify a new host reservation in one or more Kea servers. These Kea servers must be configured to use the host_cmds hooks library, and only these servers are available for selection in the DHCP Servers dropdown.

You have a choice between a subnet-level or global host reservation. Selecting a subnet using the Subnet dropdown is required for a subnet-level reservation. If the desired subnet is not displayed in the dropdown, it is possible that the selected DHCP servers do not include this subnet in their configuration. Setting the Global reservation option disables subnet selection.

To associate the new host reservation with a DHCP client, you can select one of the identifier types supported by Kea. Available identifiers differ depending on whether the user selected DHCPv4 or DHCPv6 servers. The identifier can be specified using hex or text format. For example, the hw-address is typically specified as a string of hexadecimal digits: ab:76:54:c6:45:31. In that case, select hex option. Some identifiers, e.g. circuit-id, are often specified using “printable characters”, e.g. circuit-no-1. In that case, select text option. Please refer to Host Reservations in DHCPv4 and Host Reservations in DHCPv6 for more details regarding allowed DHCP identifiers and their formats.

Further in the form, you can specify the actual reservations. It is possible to specify at most one IPv4 address. In the case of the DHCPv6 servers, it is possible to specify multiple IPv6 addresses and delegated prefixes.

The DHCPv4 siaddr, sname and file fields can be statically assigned to the clients using host reservations. The relevant values in Kea and Stork are: Next Server, Server Hostname, and Boot File Name. You can only set these values for the DHCPv4 servers. The form lacks controls for setting them when editing a DHCPv6 host.

It is possible to associate one or more client classes with a host. Kea servers assign these classes to the DHCP packets received from the client having the host reservation. Client classes are typically defined in the Kea configurations but not necessarily. For example, built-in classes like DROP have no explicit definitions in the configuration files. You can click the List button to select client classes from the list of classes explicitly defined in the configurations of the monitored Kea servers. Select the desired class names and click Insert. If the desired class name is not on the list, you can type the class name directly in the input box and press enter. Click on the cross icon next to the class name to delete it from the host reservation.

DHCP options can be added to the host reservation by clicking the Add Option button. The list of the standard DHCP options is available via the dropdown. However, if the list is missing a desired option, you can simply type the option code in the dropdown. The Always Send checkbox specifies whether the option should always be returned to a DHCP client assigned this host reservation, regardless of whether the client requests this option from the DHCP server.

Stork recognizes standard DHCP option formats. After selecting an option code, the form is adjusted to include option fields suitable for the selected option. If the option payload comprises an array of option fields, only the first field (or the first group of the record field) is displayed by default. Use the Add <field-type> button below the option code to add more fields to the array.

Note

Currently, Stork does not verify whether or not the specified options comply with the formats specified in the RFCs, nor does it check them against the runtime option definitions configured in Kea. If you specify wrong option format, Stork will try to send the option to Kea for verification, and Kea will reject the new reservation. The reservation can be submitted again after correcting the option payload.

Please use the Add <field-type> button to add suboptions to a DHCP option. Stork supports top-level options with maximum two levels of suboptions.

If a host reservation is configured in several DHCP servers, typically, all servers comprise the same set of parameters (i.e., IP addresses, hostname, boot fields, client classes and DHCP options). By default, creating a new host reservation for several servers sends an identical copy of the host reservation to each. You may choose to specify a different set of boot fields, client classes or options for different servers by selecting Configure individual server vaues at the top of the form. In this case, you must specify the complete sets of boot fields, client classes and options for each DHCP server. Leaving them blank for some servers means that these servers receive no boot fields, classes or DHCP options with the reservation.

3.5.6.5. Updating Host Reservations

In a selected host reservation’s view, click Edit button to open a form for editing host reservation information. The form automatically toggles editing DHCP options individually for each server (see above) when it detects different option sets on different servers using the reservation. Besides editing the host reservation information, it is also possible to deselect some of the servers (using the DHCP Servers dropdown), which will delete the reservation from these servers.

Use the Revert Changes button to remove all applied changes and restore the original host reservation information. Use Cancel to close the form without applying the changes.

3.5.6.6. Deleting Host Reservations

To delete a host reservation from all DHCP servers for which it is configured, click on the reservation in the host reservations list. Find the Delete button and confirm the reservation deletion. Use it with caution because this operation cannot be undone. The reservation is removed from the DHCP servers’ databases. It must be re-created to be restored.

Note

The Delete button is unavailable for host reservations configured in the Kea configuration files or when the reservations are configured in the host database, but the host_cmds hook library is not loaded.

3.5.7. Leases Search

Stork can search DHCP leases on monitored Kea servers, which is helpful for troubleshooting issues with a particular IP address or delegated prefix. It is also helpful in resolving lease allocation issues for certain DHCP clients. The search mechanism utilizes Kea control commands to find leases on the monitored servers. An operator must ensure that any Kea servers on which he intends to search the leases have the lease commands hook library loaded. Stork does not search leases on Kea instances without this library.

The leases search is available via the DHCP -> Leases Search menu. Enter one of the searched lease properties in the search box:

• IPv4 address, e.g. 192.0.2.3

• IPv6 address or delegated prefix without prefix length, 2001:db8::1

• MAC address, e.g. 01:02:03:04:05:06

• DHCPv4 Client Identifier, e.g. 01:02:03:04

• DHCPv6 DUID, e.g. 00:02:00:00:00:04:05:06:07

• Hostname, e.g. myhost.example.org

All identifier types can also be specified using the notation with spaces, e.g. 01 02 03 04 05 06, or the notation with hexadecimal digits only, e.g. 010203040506.

To search all declined leases, type state:declined. Be aware that this query may return a large result if there are many declined leases, and thus the query processing time may also increase.

Searching using partial text is currently unsupported. For example: searching by partial IPv4 address 192.0.2 is not accepted by the search box. Partial MAC address 01:02:03 is accepted but will return no results. Specify the complete MAC address instead, e.g. 01:02:03:04:05:06. Searching leases in states other than declined is also unsupported. For example, the text state:expired-reclaimed is not accepted by the search box.

The search utility automatically recognizes the specified lease type property and communicates with the Kea servers to find leases using appropriate commands. Each search attempt may result in several commands to multiple Kea servers; therefore, it may take several seconds or more before Stork displays the search results. If some Kea servers are unavailable or return an error, Stork shows leases found on the servers which returned success status, and displays a warning message containing the list of Kea servers that returned an error.

If the same lease is found on two or more Kea servers, the results list contains all that lease’s occurrences. For example, if there is a pair of servers cooperating via the High Availability hook library, the servers exchange the lease information, and each of them maintains a copy of the lease database. In that case, the lease search on these servers typically returns two occurrences of the same lease.

To display the detailed lease information, click the expand button (>) in the first column for the selected lease.

3.5.8. Kea High Availability Status

When viewing the details of the Kea application for which High Availability (HA) is enabled (via the libdhcp_ha.so hook 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; this machine may or may not be monitored by Stork. The statuses of both the local and the remote servers 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 it the ha-heartbeat command. 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 returned by Stork includes the age of the data displayed.

The Stork 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. 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 the Stork 0.8.0 release, the High Availability view also contains information about the heartbeat status between the two servers and information about failover progress.

The failover progress information is only presented when one of the active servers has been unable to communicate with the partner via refthe 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 number of “unacked” clients (clients which failed to get a lease), connecting clients (all clients currently trying to get a lease from the partner), and analyzed packets are displayed. The system administrator may use this information to diagnose why the failover transition has not taken place or when such a transition is likely to happen.

More about the High Availability status information provided by Kea can be found in the Kea ARM.

3.5.9. Viewing the Kea Log

Stork offers a simple log-viewing mechanism to diagnose issues with monitored applications.

Note

This mechanism currently only supports viewing Kea log files; viewing BIND 9 logs is not yet supported. 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 to view its logs. Next, select the Kea daemon by clicking on one of the tabs, e.g. the DHCPv4 tab. Scroll down to the Loggers section.

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 links to the log viewer are not available for them.

Clicking on the selected log file navigates to its log viewer. 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 a 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. Each time any of these buttons is clicked, the viewer discards the 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 the amount of data fetched from the monitored machine increases.

3.5.10. Viewing the Kea Configuration as a JSON Tree

Kea uses JavaScript Object Notation (JSON) to represent its configuration in the configuration files and the command channel. Parts of the Kea configuration held in the Configuration Backend are also converted to JSON and returned over the control channel in that format. Diagnosis of issues with a particular server often begins by inspecting its configuration.

In the Kea App view, select the appropriate tab for the daemon configuration to be inspected, and then click on the Raw Configuration button. The displayed tree view comprises the selected daemon’s configuration fetched using the Kea config-get command.

Note

The config-get command returns the configuration currently in use by the selected Kea server. It is a combination of the configuration read from the configuration file and from the config backend, if Kea uses the backend. Therefore, the configuration tree presented in Stork may differ (sometimes significantly) from the configuration file contents.

The nodes with complex data types can be individually expanded and collapsed. All nodes can also be expanded or collapsed by toggling the Expand button. When expanding nodes with many sub-nodes, they may be paginated to avoid degrading browser performance.

Click the Refresh button to fetch and display the latest configuration. Click Download to download the entire configuration into a text file.

Note

Some of the configuration fields may contain sensitive data (e.g. passwords or tokens). The content of these fields is hidden, and a placeholder is shown. Configurations downloaded as JSON files by users other than super-admins contain null values in place of the sensitive data.

3.5.11. Configuration Review

Kea DHCP servers are controlled by numerous configuration parameters. It poses a risk of misconfiguration or inefficient server operation when the parameters are misused. Stork can help determine typical problems in a Kea server configuration using built-in configuration checkers.

It generates configuration reports for a monitored Kea daemon when it detects its configuration has changed. To view the reports for the daemon, navigate to the application page and select one of the daemons. The Configuration Review Reports panel lists issues and proposed configuration updates generated by the configuration checkers. Each checker focuses on one particular problem.

If you consider some of the reports false alarms in your deployment, you can disable some configuration checkers for a selected daemon or globally for all daemons. Click the Checkers button to open the list of available checkers and their current state. Click on the values in the State column for the respective checkers until they are in the desired states. Besides enabling and disabling the checker, it is possible to configure it to use the globally specified setting (i.e., globally enabled or globally disabled). The global settings control the checker states for all daemons for which explicit states are not selected.

Select Configuration -> Review Checkers from the main menu to modify the global states. Use the checkboxes in the State column to modify the global states for respective checkers.

The Selectors listed for each checker inform about the types of daemons whose configurations they validate:

• each-daemon - run for all types of daemons,

• kea-daemon - run for all Kea daemons,

• kea-ca-daemon - run for Kea Control Agents,

• kea-dhcp-daemon - run for DHCPv4 and DHCPv6 daemons,

• kea-dhcp-v4-daemon - checkers run for Kea DHCPv4 daemons,

• kea-dhcp-v6-daemon - run for Kea DHCPv6 daemons

• kea-d2-daemon - run for Kea D2 daemons,

• bind9-daemon - run for Bind 9 daemons

The triggers inform in which cases the checkers are executed. Currently, there are three types of triggers:

• manual - run on user’s request,

• config change - run when daemon configuration change has been detected,

• host reservations change - run when a change in the Kea host reservations database has been detected.

The selectors and triggers are not configurable by a user.

3.5.12. Synchronizing Kea Configurations

Stork pullers periodically check Kea configurations against the local copies stored in the Stork database. These local copies are only updated when Stork detects any mismatch. This approach works fine in most cases and eliminates the overhead of unnecessarily updating the local database. However, there are possible scenarios when the mismatch between the configurations is not detected, but it is still desired to fetch and repopulate the configurations from the Kea servers to Stork.

There are many internal operations in Stork occuring when the configuration change has been detected (e.g., populating host reservations, log viewer initialization, configuration reviews, and many others). Resynchronizing the configurations from Kea triggers all these tasks. It may possibly correct some data integrity issues that may sometimes occur due to software bugs, network errors, or any other reason.

To schedule the configuration synchronization from the Kea servers, navigate to Services and then Kea Apps. Click on Resynchronize Kea Configs button. The pullers will fetch and populate the updated configuration data, but depending on the configured puller intervals, it will take some time. Ensure the pullers are not disabled on the Settings page; otherwise, the configurations will never re-synchronize.

3.6. Dashboard

The main Stork page presents a dashboard. It contains a panel with information about DHCP and a panel with events observed or noticed by the Stork server.

3.6.1. DHCP Panel

The DHCP panel includes two sections: one for DHCPv4 and one for DHCPv6. Each section contains three kinds of information:

• a list of up to five subnets with the highest pool utilization.

• a list of up to five shared networks with the highest pool utilization

• statistics about DHCP.

3.6.2. Events Panel

The Events panel presents the list of the most recent events captured by the Stork server. There are three event urgency levels: info, warning, and error. Events pertaining to the particular entities, e.g. machines or applications, provide a link to a web page containing information about the given object.

3.7. Events Page

The Events page presents a list of all events. It allows events to be filtered by:

• urgency level

• machine

• application type (Kea, BIND 9)

• daemon type (DHCPv4, DHCPv6, named, etc.)

• the user who caused given event (available only to users in the super-admin group).