systemd netlogd

systemd-netlogd

使用 Syslog 协议（RFC 5424 和 RFC 3339）通过网络将日志中的消息转发到其他主机。它可以配置为向单播和多播地址发送消息。 systemd-netlogd 使用自己的用户 systemd-journal-netlog 运行。当网络启动时开始发送日志，并在网络关闭时停止发送（使用 sd-network）。它从日志中读取并一一转发到网络。它不使用任何额外的磁盘空间。 systemd-netlogd 支持 UDP、TCP、TLS 和 DTLS（数据报传输层安全 RFC 6012）。

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从源安装

安装构建依赖项：

 # On Debian/Ubuntu
sudo apt install build-essential gperf libcap-dev libsystemd-dev pkg-config meson python3-sphinx
# On CentOS/RHEL/Fedora
sudo dnf group install 'Development Tools'
sudo dnf install gperf libcap-devel pkg-config systemd-devel meson python3-sphinx

构建并安装：

 make
sudo make install

创建用户：

sudo useradd -r -d / -s /usr/sbin/nologin -g systemd-journal systemd-journal-netlog

或通过 sysusers

/usr/lib/sysusers.d/systemd-netlogd.conf

 # Type   Name                    ID                      GECOS   Home directory  Shell
u       systemd-journal-netlog  -:systemd-journal       -       /               /bin/nologin

配置

systemd-netlogd 读取名为/etc/systemd/netlogd.conf和/etc/systemd/netlogd.conf.d/*.conf的配置文件。

[网络]部分选项

 The "[Network]" section only applies for UDP multicast address and Port:

Address=
    Controls whether log messages received by the systemd-netlogd daemon shall be forwarded to a unicast UDP address or multicast UDP network group in syslog RFC 5424 format. The the address string format is similar to socket units. See systemd.socket(1)

Protocol=
    Specifies whether to use udp, tcp, tls or dtls (Datagram Transport Layer Security) protocol. Defaults to udp.

LogFormat=
    Specifies whether to use RFC 5424 format or RFC 3339 format. Takes one of rfc5424 or rfc3339. Defaults to rfc5424.

Directory=
    Takes a directory path. Specifies whether to operate on the specified journal directory DIR instead of the default runtime and system journal paths.
          
Namespace=
    Takes a journal namespace identifier string as argument. If not specified the data collected by the default namespace is shown. If specified shows the log data of the specified namespace instead. If the namespace is specified as "*" data from all namespaces is shown, interleaved. If the namespace identifier is prefixed with "+" data from the specified namespace and the default namespace is shown, interleaved, but no other.

ConnectionRetrySec=
    Specifies the minimum delay before subsequent attempts to contact a Log server are made. Takes a time span value. The default unit is seconds, but other units may be specified, see systemd.time(5). Defaults to 30 seconds and must not be smaller than 1 second.

TLSCertificateAuthMode=
    Specifies whether to validate the certificate. Takes one of no, allow, deny, warn. Defaults to 'deny' which rejects certificates failed to validate.

TLSServerCertificate=
    Specify a custom certificate to validate the server against. Takes a path to a certificate file in PEM format.

KeepAlive=
    Takes a boolean argument. If true, the TCP/IP stack will send a keep alive message after 2h (depending on the configuration of /proc/sys/net/ipv4/tcp_keepalive_time) for all TCP streams accepted on this socket. This controls the SO_KEEPALIVE socket option (see socket(7) and the TCP Keepalive HOWTO for details.) Defaults to false.

KeepAliveTimeSec=
    Takes time (in seconds) as argument. The connection needs to remain idle before TCP starts sending keepalive probes. This controls the TCP_KEEPIDLE socket option (see socket(7) and the TCP Keepalive HOWTO for details.) Default value is 7200 seconds (2 hours).

KeepAliveIntervalSec=
    Takes time (in seconds) as argument between individual keepalive probes, if the socket option SO_KEEPALIVE has been set on this socket. This controls the TCP_KEEPINTVL socket option (see socket(7) and the TCP Keepalive HOWTO for details.) Default value is 75 seconds.

KeepAliveProbes=
    Takes an integer as argument. It is the number of unacknowledged probes to send before considering the connection dead and notifying the application layer. This controls the TCP_KEEPCNT socket option (see socket(7) and the TCP Keepalive HOWTO for details.) Default value is 9.

SendBuffer=
    Takes an integer argument controlling the receive or send buffer sizes of this socket, respectively. This controls the SO_SNDBUF socket options (see socket(7) for details.). The usual suffixes K, M, G are supported and are understood to the base of 1024.

NoDelay=
    Takes a boolean argument. TCP Nagle's algorithm works by combining a number of small outgoing messages, and sending them all at once. This controls the TCP_NODELAY socket option (see tcp(7)). Defaults to false.

可选设置

 StructuredData=
    Meta information about the syslog message, which can be used for Cloud Based syslog servers, such as Loggly

UseSysLogStructuredData=
    A boolean. Specifies whether to extract SYSLOG_STRUCTURED_DATA= from journal. Defaults to false.

UseSysLogMsgId=
    A boolean. Specifies whether to extract SYSLOG_MSGID= from journal. Defaults to false.

ExcludeSyslogFacility=
    A list of strings. Specifies the syslog facilities to skip forwarding. Possible values are: "kern", "user", "mail", "daemon", "auth", "syslog", "lpr", "news", "uucp", "cron", "authpriv", "ftp", "ntp", "security", "console", "solaris-cron", "local0", "local1", "local2", "local3", "local4", "local5", "local6" and "local7".

ExcludeSyslogLevel=
    A list of strings. Specifies the syslog levels to skip forwarding. Possible values are: "emerg", "alert", "crit", "err", "warning", "notice", "info" and "debug".

例子

示例1.UDP组播

[ Network ]
Address = 239.0 .0.1:6000
# Protocol=udp
# LogFormat=rfc5424

例2.UDP

[ Network ]
Address = 192.168 .8.101:514
# Protocol=udp
LogFormat =r fc3339

示例 3. 结构化数据

[ Network ]
Address = 192.168 .8.101:514
# Protocol=udp
LogFormat =r fc5424
StructuredData =[ 1 ab456b6-90bb-6578-abcd-5b734584aaaa@41058]

示例 4. 自定义 syslog 结构化数据和消息 ID

[ Network ]
Address = 192.168 .8.101:514
# Protocol=udp
LogFormat =r fc5424
UseSysLogStructuredData =y es
UseSysLogMsgId =y es

示例 5. 跳过具有 AUTH 或 AUTHPRIV 功能的消息以及具有 DEBUG 级别的消息

[ Network ]
Address = 192.168 .8.101:514
# Protocol=udp
LogFormat =r fc3339
ExcludeSyslogFacility =a uth authpriv
ExcludeSyslogLevel =d ebug

示例 6. 具有证书身份验证模式的 TLS

[ Network ]
Address = 192.168 .8.101:4433
Protocol =t ls
# LogFormat=rfc5424
TLSCertificateAuthMode =w arn

示例 7. 具有证书身份验证模式的 DTLS

[ Network ]
Address = 192.168 .8.101:4433
Protocol =d tls
# LogFormat=rfc5424
TLSCertificateAuthMode =a llow

UseSysLogStructuredData=和UseSysLogMsgId=的用例

 sd_journal_send (
    "MESSAGE=%s" , "Message to process" ,
    "PRIORITY=%s" , "4" ,
    "SYSLOG_FACILITY=%s" , "1" ,
    "SYSLOG_MSGID=%s" , "1011" ,
    "SYSLOG_STRUCTURED_DATA=%s" , R "([exampleSDID@32473 iut=" 3 " eventSource=" Application "])" ,
    NULL
);