The elasticsearch-http destination of syslog-ng PE can directly post log messages to an Elasticsearch deployment using the Elasticsearch Bulk API over the HTTP and Secure HTTP (HTTPS) protocols. The elasticsearch-http destination has the following options. The required options are: index(), type(), and url().
This destination is available in syslog-ng PE version 7.0.14 and later.
batch-bytes()
| Accepted values: |
number [bytes] |
| Default: |
none |
Description: Sets the maximum size of payload in a batch. If the size of the messages reaches this value, syslog-ng PE sends the batch to the destination even if the number of messages is less than the value of the batch-lines() option.
Note that if the batch-timeout() option is enabled and the queue becomes empty, syslog-ng PE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-bytes().
Available in syslog-ng PE version 7.0.12 and later.
For details on how this option influences batch mode, see Batch mode and load balancing
batch-lines()
Description: Specifies how many lines are flushed to a destination in one batch. The syslog-ng PE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.
For example, if you set batch-lines() to 100, syslog-ng PE waits for 100 messages.
If the batch-timeout() option is disabled, the syslog-ng PE application flushes the messages if it has sent batch-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng PE or in case of network sources, the connection with the client is closed, syslog-ng PE automatically sends the unsent messages to the destination.
If the batch-timeout() option is enabled and the queue becomes empty, syslog-ng PE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-lines().
For optimal performance, make sure that the syslog-ng PE source that feeds messages to this destination is configured properly: the value of the log-iw-size() option of the source must be higher than the batch-lines()*workers() of the destination. Otherwise, the size of the batches cannot reach the batch-lines() limit.
For details on how this option influences batch mode, see Batch mode and load balancing
batch-timeout()
| Type: |
time [milliseconds] |
| Default: |
-1 (disabled) |
Description: Specifies the time syslog-ng PE waits for lines to accumulate in the output buffer. The syslog-ng PE application sends batches to the destinations evenly. The timer starts when the first message arrives to the buffer, so if only few messages arrive, syslog-ng PE sends messages to the destination once every batch-timeout() milliseconds at most.
For details on how this option influences batch mode, see Batch mode and load balancing
ca-dir()
| Accepted values: |
directory name |
| Default: |
none |
Description: Name of a directory, that contains a set of trusted CA certificates in PEM format. The CA certificate files have to be named after the 32-bit hash of the subject's name. This naming can be created using the c_rehash utility in OpenSSL. For an example, see Configuring TLS on the syslog-ng clients. The syslog-ng PE application uses the CA certificates in this directory to validate the certificate of the peer.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
ca-file()
| Accepted values: |
Filename |
| Default: |
none |
Description: Name of a file that contains an X.509 CA certificate (or a certificate chain) in PEM format. The syslog-ng PE application uses this certificate to validate the certificate of the HTTPS server. If the file contains a certificate chain, the file must begin with the certificate of the host, followed by the CA certificate that signed the certificate of the host, and any other signing CAs in order.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
cert-file()
| Accepted values: |
Filename |
| Default: |
none |
Description: Name of a file, that contains an X.509 certificate (or a certificate chain) in PEM format, suitable as a TLS certificate, matching the private key set in the key-file() option. The syslog-ng PE application uses this certificate to authenticate the syslog-ng PE client on the destination server. If the file contains a certificate chain, the file must begin with the certificate of the host, followed by the CA certificate that signed the certificate of the host, and any other signing CAs in order.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
cipher-suite()
| Accepted values: |
Name of a cipher, or a colon-separated list |
| Default: |
Depends on the OpenSSL version that syslog-ng PE uses |
Description: Specifies the cipher, hash, and key-exchange algorithms used for the encryption, for example, ECDHE-ECDSA-AES256-SHA384. The list of available algorithms depends on the version of OpenSSL used to compile syslog-ng PE. To specify multiple ciphers, separate the cipher names with a colon, and enclose the list between double-quotes, for example:
cipher-suite("ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384")
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
custom-id()
| Accepted values: |
string |
| Default: |
empty string |
Description: Sets the specified value as the ID of the Elasticsearch index (_id).
delimiter()
| Accepted values: |
string |
| Default: |
newline character |
Description: By default, syslog-ng PE separates the log messages of the batch with a newline character. You can specify a different delimiter by using the delimiter() option.
For details on how this option influences batch mode, see Batch mode and load balancing
disk-buffer()
Description: This option enables putting outgoing messages into the disk-buffer file of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:
| dir() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the folder where the disk-buffer files are stored.
Note that changing the value the dir() option will not move or copy existing files from the old directory to the new one.
|
|
Caution:
When creating a new dir() option for a disk-buffer file, or modifying an existing one, make sure you delete the persist file.
syslog-ng PE creates disk-buffer files based on the path recorded in the persist file. Therefore, if the persist file is not deleted after modifying the dir() option, then following a restart, syslog-ng PE will look for or create disk-buffer files in their old location. To ensure that syslog-ng PE uses the new dir() setting, the persist file must not contain any information about the destinations which the disk-buffer file in question belongs to. | |
| disk-buf-size() |
| Type: |
number [bytes] |
| Default: |
|
| Description: This is a required option. The maximum size of the disk-buffer file in bytes. The minimum value is 1048576 bytes. If you set a smaller value, the minimum value will be used automatically. It replaces the old log-disk-fifo-size() option. |
| mem-buf-length() |
| Type: |
number [messages] |
| Default: |
10000 |
| Description: Use this option if the option reliable() is set to no. This option contains the number of messages stored in overflow queue. It replaces the old log-fifo-size() option. It inherits the value of the global log-fifo-size() option if provided. If it is not provided, the default value is 10000 messages. Note that this option will be ignored if the option reliable() is set to yes. |
| mem-buf-size() |
| Type: |
number [bytes] |
| Default: |
163840000 |
| Description: Use this option if the option reliable() is set to yes. This option contains the size of the messages in bytes that is used in the memory part of the disk-buffer file. It replaces the old log-fifo-size() option. It does not inherit the value of the global log-fifo-size() option, even if it is provided. Note that this option will be ignored if the option reliable() is set to no. |
| quot-size() |
| Type: |
number [messages] |
| Default: |
1000 |
|
Description: The number of messages stored in the output buffer of the destination. Note that if you change the value of this option and the disk-buffer file already exists, the change will take effect when the disk-buffer file becomes empty. |
| reliable() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng PE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng PE crash. This solution provides a slower, but reliable disk-buffer option. It is created and initialized at startup and gradually grows as new messages arrive. If set to no, the normal disk-buffer option will be used. This provides a faster, but less reliable disk-buffer option.
|
|
Caution: Hazard of data loss!
If you change the value of reliable() option when there are messages in the disk-buffer file, the messages stored in the disk-buffer file will be lost. | |
| truncate-size-ratio() |
| Type: |
number (for percentage) between 0 and 1 |
| Default: |
0.1 (10%) |
|
Description: Limits the truncation of the disk-buffer file. Truncating the disk-buffer file can slow down disk I/O operations, but it saves disk space. As a result, syslog-ng PE only truncates the file if the possible disk gain is more than truncate-size-ratio() times disk-buf-size().
|
|
Caution:
One Identity recommends that you do not modify the value of the truncate-size-ratio() option unless you are fully aware of the potential performance implications. | |
Example: Examples for using disk-buffer()
In the following case, reliable disk-buffer() is used.
destination d_demo {
network("127.0.0.1"
port(3333)
disk-buffer(
mem-buf-size(10000)
disk-buf-size(2000000)
reliable(yes)
dir("/tmp/disk-buffer")
)
);
};
In the following case normal disk-buffer() is used.
destination d_demo {
network("127.0.0.1"
port(3333)
disk-buffer(
mem-buf-length(10000)
disk-buf-size(2000000)
reliable(no)
dir("/tmp/disk-buffer")
)
);
};
hook-commands()
Description: This option allows running external programs when the relevant driver is initialized or torn down. The hook-commands() can be used with all source and destination drivers with the exception of the usertty() and internal() drivers.
NOTE: The syslog-ng PE application must be able to start and restart the external program, and have the necessary permissions to do so. For example, if your host is running AppArmor or SELinux, you might have to modify your AppArmor or SELinux configuration to enable syslog-ng PE to execute external applications.
Using the hook-commands() when syslog-ng PE starts or stops
To run an external program when syslog-ng PE starts or stops, use the following options:
|
startup() |
|
Type: |
string |
|
Default: |
N/A |
|
Description: Defines the external program that is run when syslog-ng PE starts. |
|
shutdown() |
|
Type: |
string |
|
Default: |
N/A |
|
Description: Defines the external program that is executed when syslog-ng PE stops. |
Using the hook-commands() when syslog-ng PE reloads
To run an external program when the syslog-ng PE configuration is initiated or torn down (for example, on startup/shutdown or during a syslog-ng PE reload), use the following options:
|
setup() |
|
Type: |
string |
|
Default: |
N/A |
|
Description: Defines an external program that is run when the syslog-ng PE configuration is initiated, for example, on startup or during a syslog-ng PE reload. |
|
teardown() |
|
Type: |
string |
|
Default: |
N/A |
|
Description: Defines an external program that is run when the syslog-ng PE configuration is stopped or torn down, for example, on shutdown or during a syslog-ng PE reload. |
Example: Using the hook-commands() with a network source
In the following example, the hook-commands() is used with the network() driver and it opens an iptables port automatically when syslog-ng PE is started/stopped.
The assumption in this example is that the LOGCHAIN chain is part of a larger ruleset that routes traffic to it. Whenever the syslog-ng PE created rule is there, packets can flow (otherwise the port is closed).
source {
network(transport(udp)
hook-commands(
startup("iptables -I LOGCHAIN 1 -p udp --dport 514 -j ACCEPT")
shutdown("iptables -D LOGCHAIN 1")
;)
);
};
index()
| Accepted values: |
string or template |
| Default: |
None |
Description: The name of the Elasticsearch index where Elasticsearch will store the messages received from syslog-ng PE. This option is mandatory for this destination.
You can use macros and template functions, but you must ensure that the resolved template contains only characters that Elasticsearch permits in the name of the index. The syslog-ng PE application does not validate the name of the index. For details on the characters permitted in the name of Elasticsearch indices, see the documentation of Elasticsearch.
log-fifo-size()
| Type: |
number |
| Default: |
Use global setting. |
Description: The number of messages that the output queue can store.
key-file()
| Accepted values: |
Filename |
| Default: |
none |
Description: Path and name of a file that contains a private key in PEM format, suitable as a TLS key. If properly configured, the syslog-ng PE application uses this private key and the matching certificate (set in the cert-file() option) to authenticate the syslog-ng PE client on the destination server.
This destination supports only unencrypted key files (that is, the private key cannot be password-protected).
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
password()
Description: The password that syslog-ng PE uses to authenticate on the server where it sends the messages.
peer-verify()
| Accepted values: |
yes | no |
| Default: |
yes |
Description: Verification method of the peer. The following table summarizes the possible options and their results depending on the certificate of the peer.
| Local peer-verify() setting |
no (optional-untrusted) |
TLS-encryption |
TLS-encryption |
TLS-encryption |
| yes (required-trusted) |
rejected connection |
rejected connection |
TLS-encryption |
For untrusted certificates only the existence of the certificate is checked, but it does not have to be valid — syslog-ng accepts the certificate even if it is expired, signed by an unknown CA, or its CN and the name of the machine mismatches.
|
|
Caution:
When validating a certificate, the entire certificate chain must be valid, including the CA certificate. If any certificate of the chain is invalid, syslog-ng PE will reject the connection. |
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
persist-name()
| Type: |
string |
| Default: |
None |
Description:If you receive the following error message during syslog-ng PE startup, set the persist-name() option of the duplicate drivers:
Error checking the uniqueness of the persist names, please override it with persist-name option. Shutting down.
This error occurs if you use identical drivers in multiple sources, for example, if you configure two file sources to read from the same file. In this case, set the persist-name() of the drivers to a custom string, for example, persist-name("example-persist-name1").
proxy()
| Type: |
The proxy server address, in proxy("PROXY_IP:PORT") format.
For example, proxy("http://myproxy:3128") |
| Default: |
None |
Description:
The proxy() option enables you to configure the elasticsearch-http driver to use a specific HTTP proxy for all HTTP-based destinations, instead of using the proxy that is configured for the system.
If you do not set the proxy() option, the elasticsearch-http driver uses the http_proxy and https_proxy environment variables, as shown in CURLOPT_PROXY explained.
NOTE: Configuring the proxy() option overwrites the default http_proxy and https_proxy environment variables.
retries()
| Type: |
number [of attempts] |
| Default: |
3 |
Description: The number of times syslog-ng PE attempts to send a message to this destination. If syslog-ng PE could not send a message, it will try again until the number of attempts reaches retries(), then drops the message.
To handle HTTP error responses, if the HTTP server returns 5xx codes, syslog-ng PE will attempt to resend messages until the number of attempts reaches retries. If the HTTP server returns 4xx codes, syslog-ng PE will drop the messages.
ssl-version()
| Type: |
string |
| Default: |
None, uses the libcurl default |
Description: Specifies the permitted SSL/TLS version. Possible values: sslv2, sslv3, tlsv1, tlsv1_0, tlsv1_1, tlsv1_2, tlsv1_3.
An alternative way to specify this option is to put it into a tls() block, together with any other TLS options. This allows you to separate these options and ensure better readability.
Make sure that you specify TLS options either using their own dedicated option (ca-dir(), ca-file(), cert-file(), cipher-suite(), key-file(), peer-verify(), and ssl-version()), or using the tls() block and inserting the relevant options within tls(). Avoid mixing the two methods. If you do specify TLS options in both ways, the one that comes later in the configuration file will take effect.
Declaration
destination d_elasticsearch-http {
elasticsearch-http(
url("http://your-elasticsearch-server:9200/_bulk")
type("")
index("example-index")
tls(
ca-dir("dir")
ca-file("ca")
cert-file("cert")
cipher-suite("cipher")
key-file("key")
peer-verify(yes|no)
ssl-version(<the permitted SSL/TLS version>)
)
);
};
throttle()
Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using the disk-buffer option as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.
type()
| Type: |
string or template |
| Default: |
N/A |
Description: The type of the Elasticsearch index. Use an empty string to omit the type from the index, for example, type("").
timeout()
| Type: |
number [seconds] |
| Default: |
10 |
Description: The value (in seconds) to wait for an operation to complete, and attempt to reconnect the server if exceeded.
url()
| Type: |
URL or list of URLs, for example, url("site1" "site2") |
| Default: |
N/A |
Description: Specifies the hostname or IP address and optionally the port number of the Elasticsearch indexer. Use a colon (:) after the address to specify the port number of the server. For example: http://your-elasticsearch-indexer.server:8088/_bulk
This option is mandatory for this destination.
Make sure that the URL ends with _bulk, this is the Elasticsearch API endpoint that properly parses the messages sent by syslog-ng PE.
In case the server on the specified URL returns a redirect request, syslog-ng PE automatically follows maximum 3 redirects. Only HTTP and HTTPS based redirections are supported.
Starting with version 7.0.12, you can specify multiple URLs, for example, url("site1" "site2"). In this case, syslog-ng PE sends log messages to the specified URLs in a load-balance fashion. This means that syslog-ng PE sends each message to only one URL. For example, you can use this to send the messages to a set of ingestion nodes or indexers of your SIEM solution if a single node cannot handle the load. Note that the order of the messages as they arrive on the servers can differ from the order syslog-ng PE has received them, so use load-balancing only if your server can use the timestamp from the messages. If the server uses the timestamp when it receives the messages, the order of the messages will be incorrect.
|
|
Caution:
If you set multiple URLs in the url() option, set the persist-name() option as well to avoid data loss. |
user()
Description: The username that syslog-ng PE uses to authenticate on the server where it sends the messages.
use-system-cert-store()
| Type: |
yes | no |
| Default: |
no |
Description: Use the certificate store of the system for verifying HTTPS certificates. For details, see the curl documentation.
workers()
Description: Specifies the number of worker threads (at least 1) that syslog-ng PE uses to send messages to the server. Increasing the number of worker threads can drastically improve the performance of the destination.
|
|
Caution:
Hazard of data loss!
When you use more than one worker threads together with the disk-buffer option, syslog-ng PE creates a separate disk-buffer file for each worker thread. This means that decreasing the number of workers can result in losing data currently stored in the disk-buffer files. Do not decrease the number of workers when the disk-buffer files are in use. |
If you are using load-balancing (that is, you have configured multiple servers in the url() option), increase the number of worker threads at least to the number of servers. For example, if you have set three URLs (url("site1" "site2" "site3")), set the workers() option to 3 or more.
The file driver is one of the most important destination drivers in syslog-ng. It allows to output messages to the specified text file, or to a set of files.
The destination filename may include macros which get expanded when the message is written, thus a simple file() driver may create several files: for example, syslog-ng PE can store the messages of client hosts in a separate file for each host. For more information on available macros see Macros of syslog-ng PE.
If the expanded filename refers to a directory which does not exist, it will be created depending on the create-dirs() setting (both global and a per destination option).
The file() has a single required parameter that specifies the filename that stores the log messages. For the list of available optional parameters, see file() destination options.
Declaration
file(filename options());
Example: Using the file() driver
destination d_file { file("/var/log/messages"); };
Example: Using the file() driver with macros in the file name and a template for the message
destination d_file {
file("/var/log/${YEAR}.${MONTH}.${DAY}/messages"
template("${HOUR}:${MIN}:${SEC} ${TZ} ${HOST} [${LEVEL}] ${MESSAGE}\n")
template-escape(no)
);
};
NOTE:
When using this destination, update the configuration of your log rotation program to rotate these files. Otherwise, the log files can become very large.
Also, after rotating the log files, reload syslog-ng PE using the syslog-ng-ctl reload command, or use another method to send a SIGHUP to syslog-ng PE.
|
|
Caution:
Since the state of each created file must be tracked by syslog-ng, it consumes some memory for each file. If no new messages are written to a file within 60 seconds (controlled by the time-reap() global option), it is closed, and its state is freed.
Exploiting this, a DoS attack can be mounted against the system. If the number of possible destination files and its needed memory is more than the amount available on the syslog-ng server.
The most suspicious macro is ${PROGRAM}, where the number of possible variations is rather high. Do not use the ${PROGRAM} macro in insecure environments. |
The file() driver outputs messages to the specified text file, or to a set of files. The file() destination has the following options:
|
|
Caution:
When creating several thousands separate log files, syslog-ng might not be able to open the required number of files. This might happen for example, when using the ${HOST} macro in the filename while receiving messages from a large number of hosts. To overcome this problem, adjust the --fd-limit command-line parameter of syslog-ng or the global ulimit parameter of your host. For setting the --fd-limit command-line parameter of syslog-ng see the The syslog-ng manual page manual page. For setting the ulimit parameter of the host, see the documentation of your operating system. |
create-dirs()
| Type: |
yes or no |
| Default: |
no |
Description: Enable creating non-existing directories when creating files or socket files.
dir-group()
| Type: |
string |
| Default: |
Use the global settings |
Description: The group of the directories created by syslog-ng. To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-group().
dir-owner()
| Type: |
string |
| Default: |
Use the global settings |
Description: The owner of the directories created by syslog-ng. To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-owner().
Starting with version 7.0.9, the default value of this option is -1, so syslog-ng PE does not change the ownership, unless explicitly configured to do so.
dir-perm()
| Type: |
number |
| Default: |
Use the global settings |
Description: The permission mask of directories created by syslog-ng. Log directories are only created if a file after macro expansion refers to a non-existing directory, and directory creation is enabled (see also the create-dirs() option). For octal numbers prefix the number with 0, for example, use 0755 for rwxr-xr-x.
To preserve the original properties of an existing directory, use the option without specifying an attribute: dir-perm(). Note that when creating a new directory without specifying attributes for dir-perm(), the default permission of the directories is masked with the umask of the parent process (typically 0022).
disk-buffer()
Description: This option enables putting outgoing messages into the disk-buffer file of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:
| dir() |
| Type: |
string |
| Default: |
N/A |
|
Description: Defines the folder where the disk-buffer files are stored.
Note that changing the value the dir() option will not move or copy existing files from the old directory to the new one.
|
|
Caution:
When creating a new dir() option for a disk-buffer file, or modifying an existing one, make sure you delete the persist file.
syslog-ng PE creates disk-buffer files based on the path recorded in the persist file. Therefore, if the persist file is not deleted after modifying the dir() option, then following a restart, syslog-ng PE will look for or create disk-buffer files in their old location. To ensure that syslog-ng PE uses the new dir() setting, the persist file must not contain any information about the destinations which the disk-buffer file in question belongs to. | |
| disk-buf-size() |
| Type: |
number [bytes] |
| Default: |
|
| Description: This is a required option. The maximum size of the disk-buffer file in bytes. The minimum value is 1048576 bytes. If you set a smaller value, the minimum value will be used automatically. It replaces the old log-disk-fifo-size() option. |
| mem-buf-length() |
| Type: |
number [messages] |
| Default: |
10000 |
| Description: Use this option if the option reliable() is set to no. This option contains the number of messages stored in overflow queue. It replaces the old log-fifo-size() option. It inherits the value of the global log-fifo-size() option if provided. If it is not provided, the default value is 10000 messages. Note that this option will be ignored if the option reliable() is set to yes. |
| mem-buf-size() |
| Type: |
number [bytes] |
| Default: |
163840000 |
| Description: Use this option if the option reliable() is set to yes. This option contains the size of the messages in bytes that is used in the memory part of the disk-buffer file. It replaces the old log-fifo-size() option. It does not inherit the value of the global log-fifo-size() option, even if it is provided. Note that this option will be ignored if the option reliable() is set to no. |
| quot-size() |
| Type: |
number [messages] |
| Default: |
1000 |
|
Description: The number of messages stored in the output buffer of the destination. Note that if you change the value of this option and the disk-buffer file already exists, the change will take effect when the disk-buffer file becomes empty. |
| reliable() |
| Type: |
yes|no |
| Default: |
no |
|
Description: If set to yes, syslog-ng PE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng PE crash. This solution provides a slower, but reliable disk-buffer option. It is created and initialized at startup and gradually grows as new messages arrive. If set to no, the normal disk-buffer option will be used. This provides a faster, but less reliable disk-buffer option.
|
|
Caution: Hazard of data loss!
If you change the value of reliable() option when there are messages in the disk-buffer file, the messages stored in the disk-buffer file will be lost. | |
| truncate-size-ratio() |
| Type: |
number (for percentage) between 0 and 1 |
| Default: |
0.1 (10%) |
|
Description: Limits the truncation of the disk-buffer file. Truncating the disk-buffer file can slow down disk I/O operations, but it saves disk space. As a result, syslog-ng PE only truncates the file if the possible disk gain is more than truncate-size-ratio() times disk-buf-size().
|
|
Caution:
One Identity recommends that you do not modify the value of the truncate-size-ratio() option unless you are fully aware of the potential performance implications. | |
Example: Examples for using disk-buffer()
In the following case, reliable disk-buffer() is used.
destination d_demo {
network("127.0.0.1"
port(3333)
disk-buffer(
mem-buf-size(10000)
disk-buf-size(2000000)
reliable(yes)
dir("/tmp/disk-buffer")
)
);
};
In the following case normal disk-buffer() is used.
destination d_demo {
network("127.0.0.1"
port(3333)
disk-buffer(
mem-buf-length(10000)
disk-buf-size(2000000)
reliable(no)
dir("/tmp/disk-buffer")
)
);
};
flags()
| Type: |
no-multi-line, syslog-protocol, threaded |
| Default: |
empty set |
Description: Flags influence the behavior of the destination driver.
-
no-multi-line: The no-multi-line flag disables line-breaking in the messages: the entire message is converted to a single line.
-
syslog-protocol: The syslog-protocol flag instructs the driver to format the messages according to the new IETF syslog protocol standard (RFC5424), but without the frame header. If this flag is enabled, macros used for the message have effect only for the text of the message, the message header is formatted to the new standard. Note that this flag is not needed for the syslog driver, and that the syslog driver automatically adds the frame header to the messages.
-
threaded: The threaded flag enables multithreading for the destination. For details on multithreading, see Multithreading and scaling in syslog-ng PE.
NOTE: The file destination uses multiple threads only if the destination filename contains macros.
flush-lines()
| Type: |
number |
| Default: |
Use global setting. |
Description: Specifies how many lines are flushed to a destination at a time. The syslog-ng PE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.
The syslog-ng PE application flushes the messages if it has sent flush-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng PE or in case of network sources, the connection with the client is closed, syslog-ng PE automatically sends the unsent messages to the destination.
For optimal performance when sending messages to a syslog-ng PE server, make sure that the flush-lines() is smaller than the window size set using the log-iw-size() option in the source of your server.
flush-timeout() (DEPRECATED)
| Type: |
time in milliseconds |
| Default: |
Use global setting. |
Description: This is a deprecated option. Specifies the time syslog-ng waits for lines to accumulate in its output buffer. For details, see the flush-lines() option.
frac-digits()
Description: The syslog-ng PE application can store fractions of a second in the timestamps according to the ISO8601 format. The frac-digits() parameter specifies the number of digits stored. The digits storing the fractions are padded by zeros if the original timestamp of the message specifies only seconds. Fractions can always be stored for the time the message was received.
NOTE: The syslog-ng PE application can add the fractions to non-ISO8601 timestamps as well.
NOTE: As syslog-ng PE is precise up to the microsecond, when the frac-digits() option is set to a value higher than 6, syslog-ng PE will truncate the fraction seconds in the timestamps after 6 digits.
fsync()
| Type: |
yes or no |
| Default: |
no |
Description: Forces an fsync() call on the destination fd after each write.
NOTE: Enabling this option may seriously degrade performance.
group()
| Type: |
string |
| Default: |
Use the global settings |
Description: Set the group of the created file to the one specified. To preserve the original properties of an existing file, use the option without specifying an attribute: group().
local-time-zone()
| Type: |
name of the timezone, or the timezone offset |
| Default: |
The local timezone. |
Description: Sets the timezone used when expanding filename and tablename templates.
The timezone can be specified as using the name of the (for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format (for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.
log-fifo-size()
| Type: |
number |
| Default: |
Use global setting. |
Description: The number of messages that the output queue can store.
mark-freq()
| Accepted values: |
number [seconds] |
| Default: |
1200 |
Description: An alias for the obsolete mark() option, retained for compatibility with syslog-ng version 1.6.x.
The number of seconds between two MARK messages. MARK messages are generated when there was no message traffic to inform the receiver that the connection is still alive. If set to zero (0), no MARK messages are sent. The mark-freq() can be set for global option and/or every MARK capable destination driver if mark-mode() is periodical or dst-idle or host-idle. If mark-freq() is not defined in the destination, then the mark-freq() will be inherited from the global options. If the destination uses internal mark-mode(), then the global mark-freq() will be valid (does not matter what mark-freq() set in the destination side).
mark-mode()
| Accepted values: |
internal | dst-idle | host-idle | periodical | none | global |
| Default: |
internal for pipe, program drivers
none for file, unix-dgram, unix-stream drivers
global for syslog, tcp, udp destinations
host-idle for global option |
Description: The mark-mode() option can be set for the following destination drivers: file(), program(), unix-dgram(), unix-stream(), network(), pipe(), syslog() and in global option.
-
internal: When internal mark mode is selected, internal source should be placed in the log path as this mode does not generate mark by itself at the destination. This mode only yields the mark messages from internal source. This is the mode as syslog-ng PE 3.x worked. MARK will be generated by internal source if there was NO traffic on local sources:
file(), pipe(), unix-stream(), unix-dgram(), program()
-
dst-idle: Sends MARK signal if there was NO traffic on destination drivers. MARK signal from internal source will be dropped.
MARK signal can be sent by the following destination drivers: network(), syslog(), program(), file(), pipe(), unix-stream(), unix-dgram().
-
host-idle: Sends MARK signal if there was NO local message on destination drivers. For example, MARK is generated even if messages were received from tcp. MARK signal from internal source will be dropped.
MARK signal can be sent by the following destination drivers: network(), syslog(), program(), file(), pipe(), unix-stream(), unix-dgram().
-
periodical: Sends MARK signal perodically, regardless of traffic on destination driver. MARK signal from internal source will be dropped.
MARK signal can be sent by the following destination drivers: network(), syslog(), program(), file(), pipe(), unix-stream(), unix-dgram().
-
none: Destination driver drops all MARK messages. If an explicit mark-mode() is not given to the drivers where none is the default value, then none will be used.
-
global: Destination driver uses the global mark-mode() setting. Note that setting the global mark-mode() to global causes a syntax error in syslog-ng PE.
NOTE: In case of dst-idle, host-idle and periodical, the MARK message will not be written in the destination, if it is not open yet.
Available in syslog-ng PE 4 LTS and later.
overwrite-if-older()
| Type: |
number (seconds) |
| Default: |
0 |
Description: If set to a value higher than 0, syslog-ng PE checks when the file was last modified before starting to write into the file. If the file is older than the specified amount of time (in seconds), then syslog-ng removes the existing file and opens a new file with the same name. In combination with for example, the ${WEEKDAY} macro, this can be used for simple log rotation, in case not all history has to be kept. (Note that in this weekly log rotation example if its Monday 00:01, then the file from last Monday is not seven days old, because it was probably last modified shortly before 23:59 last Monday, so it is actually not even six days old. So in this case, set the overwrite-if-older() parameter to a-bit-less-than-six-days, for example, to 518000 seconds.
owner()
| Type: |
string |
| Default: |
Use the global settings |
Description: Set the owner of the created file to the one specified. To preserve the original properties of an existing file, use the option without specifying an attribute: owner().
pad-size()
Description: If set, syslog-ng PE will pad output messages to the specified size (in bytes). Some operating systems (such as HP-UX) pad all messages to block boundary. This option can be used to specify the block size. (HP-UX uses 2048 bytes).
|
|
Caution:
Hazard of data loss! If the size of the incoming message is larger than the previously set pad-size() value, syslog-ng will truncate the message to the specified size. Therefore, all message content above that size will be lost. |
perm()
| Type: |
number |
| Default: |
Use the global settings |
Description: The permission mask of the file if it is created by syslog-ng. For octal numbers prefix the number with 0, for example, use 0755 for rwxr-xr-x.
To preserve the original properties of an existing file, use the option without specifying an attribute: perm().
suppress()
| Type: |
seconds |
| Default: |
0 (disabled) |
Description: If several identical log messages would be sent to the destination without any other messages between the identical messages (for example, an application repeated an error message ten times), syslog-ng can suppress the repeated messages and send the message only once, followed by the Last message repeated n times. message. The parameter of this option specifies the number of seconds syslog-ng waits for identical messages.
template()
| Type: |
string |
| Default: |
A format conforming to the default logfile format. |
Description: Specifies a template defining the logformat to be used in the destination. Macros are described in Macros of syslog-ng PE. Please note that for network destinations it might not be appropriate to change the template as it changes the on-wire format of the syslog protocol which might not be tolerated by stock syslog receivers (like syslogd or syslog-ng itself). For network destinations make sure the receiver can cope with the custom format defined.
template-escape()
| Type: |
yes or no |
| Default: |
no |
Description: Turns on escaping for the ', ", and backspace characters in templated output files. This is useful for generating SQL statements and quoting string contents so that parts of the log message are not interpreted as commands to the SQL server.
time-zone()
| Type: |
name of the timezone, or the timezone offset |
| Default: |
unspecified |
Description: Convert timestamps to the timezone specified by this option. If this option is not set, then the original timezone information in the message is used. Converting the timezone changes the values of all date-related macros derived from the timestamp, for example, HOUR. For the complete list of such macros, see Date-related macros.
The timezone can be specified as using the name of the (for example, time-zone("Europe/Budapest")), or as the timezone offset in +/-HH:MM format (for example, +01:00). On Linux and UNIX platforms, the valid timezone names are listed under the /usr/share/zoneinfo directory.
ts-format()
| Type: |
rfc3164, bsd, rfc3339, iso |
| Default: |
rfc3164 |
Description: Override the global timestamp format (set in the global ts-format() parameter) for the specific destination. For details, see ts-format().
