SYNOPSISpmproxy [-Af] [-C dirname] [-i ipaddress] [-l logfile] [-L bytes] [-M certname] [-p port[,port ...] [-P passfile] [-U username] [-x file]
DESCRIPTIONpmproxy acts as a protocol proxy for pmcd(1), allowing Performance Co-Pilot (PCP) monitoring clients to connect to one or more pmcd(1) instances via pmproxy.
Normally pmproxy is deployed in a firewall domain, or on a ``head'' node of a cluster where the IP (Internet Protocol) address of the hosts where pmcd(1) is running may be unknown to the PCP monitoring clients, although the IP address of the host where pmproxy is running is known to these clients. Similarly, the clients may have network connectivity only to the host where pmproxy is running, while there is network connectivity from that host to the hosts of interest where pmcd(1) is running.
The behaviour of the PCP monitoring clients is controlled by either the PMPROXY_HOST environment variable or through the extended hostname specification (see PCPIntro(1) for details). If neither of these mechanisms is used, clients will make their connections directly to pmcd(1). If the proxy hostname syntax is used or PMPROXY_HOST is set, then this should be the hostname or IP address of the system where pmproxy is running, and the clients will connect to pmcd(1) indirectly through the protocol proxy services of pmproxy.
The options to pmproxy are as follows.
- Disable service advertisement. By default, pmproxy will advertise its presence on the network using any available mechanisms (such as Avahi/DNS-SD), assisting remote monitoring tools with finding it. These mechanisms are disabled with this option.
- -C dirname
- Specify the path to the Network Security Services certificate database, for (optional) secure connections. The default is /etc/pki/nssdb. Refer also to the -P option. If it does not already exist, this database can be created using the certutil utility. This process and other certificate database maintenance information is provided in the PCPIntro(1) manual page and the online PCP tutorials.
- By default pmproxy is started as a daemon. The -f option indicates that it should run in the foreground. This is most useful when trying to diagnose problems with establishing connections.
- -i ipaddress
- This option is usually only used on hosts with more than one network interface (very common for firewall and ``head'' node hosts where pmproxy is most likely to be deployed). If no -i options are specified pmproxy accepts PCP client connections on any of its host's IP addresses. The -i option is used to specify explicitly an IP address that PCP client connections should be accepted on. ipaddress should be in the standard dotted form (e.g. 188.8.131.52). The -i option may be used multiple times to define a list of IP addresses. When one or more -i options is specified, attempted connections made on any other IP addresses will be refused.
- -l logfile
- By default a log file named pmproxy.log is written in the current directory. The -l option causes the log file to be written to logfile instead of the default. If the log file cannot be created or is not writable, output is written to the standard error instead.
- -L bytes
- PDUs received by pmproxy from PCP monitoring clients are restricted to a maximum size of 65536 bytes by default to defend against Denial of Service attacks. The -L option may be used to change the maximum incoming PDU size.
- -M certname
- By default, pmproxy will try to use a certificate called PCP Collector certificate in its server role. The -M option allows this to be changed.
- -P passfile
- Specify the path to a file containing the Network Security Services certificate database password for (optional) secure connections, and for databases that are password protected. Refer also to the -C option. When using this option, great care should be exercised to ensure appropriate ownership ("pcp" user, typically) and permissions on this file (0400, so as to be unreadable by any user other than the user running the pmproxy process).
- -U username
- Assume the identity of username before starting to accept incoming packets from PCP monitoring clients.
- -x file
- Before the pmproxy logfile can be opened, pmproxy may encounter a fatal error which prevents it from starting. By default, the output describing this error is sent to /dev/tty but it may redirected to file.
STARTING AND STOPPING PMPROXYNormally, pmproxy is started automatically at boot time and stopped when the system is being brought down. Under certain circumstances it is necessary to start or stop pmproxy manually. To do this one must become superuser and type
# $PCP_RC_DIR/pmproxy start
to start pmproxy, or
# $PCP_RC_DIR/pmproxy stop
to stop pmproxy. Starting pmproxy when it is already running is the same as stopping it and then starting it again.
Normally pmproxy listens for PCP client connections on TCP/IP port number 44322 (registered at http://www.iana.org/). Either the environment variable PMPROXY_PORT -p command line option may be used to specify alternative port number(s) when PMPROXY_PORT or the -p command line option may be used to specify alternative port number(s) when pmproxy is started; in each case, the specification is a comma-separated list of one or more numerical port numbers. Should both methods be used or multiple -p options appear on the command line, pmproxy will listen on the union of the set of ports specified via all -p options and the PMPROXY_PORT environment variable. If non-default ports are used with pmproxy care should be taken to ensure that PMPROXY_PORT is also set in the environment of any client application that will connect to pmproxy, or that the extended host specification syntax is used (see PCPIntro(1) for details).
- command line options for pmproxy when launched from $PCP_RC_DIR/pmproxy All the command line option lines should start with a hyphen as the first character.
- additional environment variables that will be set when pmproxy executes. Only settings of the form "PMPROXY_VARIABLE=value" will be honoured.
when started automatically)
All messages and diagnostics are directed here
- default Network Security Services (NSS) certificate database directory, used for optional Secure Socket Layer connections. This database can be created and queried using the NSS certutil tool, amongst others.
ENVIRONMENTIn addition to the PCP environment variables described in the PCP ENVIRONMENT section below, there are several environment variables that influence the interactions between a PCP monitoring client, pmcd and pmcd(1).
- For the PCP monitoring client this (or the default port number) is passed to pmproxy and used to connect to pmcd(1). In the environment of pmproxy PMCD_PORT is not used.
- For the PCP monitoring client this is the hostname or IP address of the host where pmproxy is running. In recent versions of PCP (since version 3) this has been superseded by the extended hostname syntax (see PCPIntro(1) for details).
- For the PCP monitoring client this is the port on which pmproxy will accept connections. The default is 44322.
- PMCD_CONNECT_TIMEOUT, PMCD_RECONNECT_TIMEOUT and PMCD_REQUEST_TIMEOUT
- (see PCPIntro(1)) For the PCP monitoring client, setting these environment variables will modify the timeouts used for interactions between the client and pmproxy (independent of which pmcd(1) is being used). For pmproxy these same environment variables control the timeouts between pmproxy and all pmcd(1) instances (independent of which monitoring client is involved).
If set to the value 1, the PMPROXY_LOCAL environment variable will cause pmproxy to run in a localhost-only mode of operation, where it binds only to the loopback interface.
The PMPROXY_MAXPENDING variable can be set to indicate the maximum length to which the queue of pending client connections may grow.
PCP ENVIRONMENTEnvironment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. On each installation, the file /etc/pcp.conf contains the local values for these variables. The PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(5).
DIAGNOSTICSIf pmproxy is already running the message "Error: OpenRequestSocket bind: Address already in use" will appear. This may also appear if pmproxy was shutdown with an outstanding request from a client. In this case, a request socket has been left in the TIME_WAIT state and until the system closes it down (after some timeout period) it will not be possible to run pmproxy.
In addition to the standard PCP debugging flags, see pmdbg(1), pmproxy currently uses DBG_TRACE_CONTEXT for tracing client connections and disconnections