Month: May 2019

Soap

SOAP is a relatively simple protocol for computers on a network to exchange information. The main feature of SOAP is that all messages to been exchanged are summarized in XML.

<?xml version='1.0' encoding='UTF-8'?>
<SOAP-ENV:Envelope
	xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
	xmlns:xsi="http://www.w3.org/1999/XMLSchema-instance"
	xmlns:xsd="http://www.w3.org/1999/XMLSchema">
	<SOAP-ENV:Body>
		<ns1:getRate
			xmlns:ns1="urn:demo1:exchange"
			>
			<country1 xsi:type="xsd:string">USA</country1>
			<country2 xsi:type="xsd:string">Japan</country2>
		</ns1:getRate>
	</SOAP-ENV:Body>
</SOAP-ENV:Envelop>

AWS subnet

A subnet is an address space that further divides the VPC. A subnet is always created in one AZ, and it is not possible to create a subnet that spans multiple AZs.

UnHealthyHostCount, Latency

UnHealthyHostCount
Number of healthy EC2 instances registered with the load balancer in the specified Availability Zone. Hosts that do not fail the health check beyond the unhealthy threshold are considered healthy. When evaluating this metric, the dimensions should be defined by LoadBalancerName and AvailabilityZone.
This metric represents the number of healthy instances in the specified Availability Zone. Instances may become unhealthy due to connection problems such as non-200 responses (for HTTP and HTTPS health checks) and timeouts when doing health checks. In order to get the total number of all healthy hosts, this metric needs to get each registered AvailabilityZone and add all metrics together.

Latency
The elapsed time from request leaving the load balancer to receiving the corresponding response.

Amazon ElastiCache

Amazon ElastiCache is a web service that makes it easy to deploy and run server nodes compliant with Memcached or Redis protocols in the cloud. Amazon ElastiCache improves web application performance by enabling the retrieval of information from a fast managed in-memory system without relying entirely on slod disk-based databases. This service simplifies the management, monitoring, and operation of the in-memory environment and reduces the load so that engineering resources can be concentrated on application development. With Amazon ElastiCache, you can improve the loading and response times of user actions and queries, as well as reduce the costs associated with scaling web applications.

AWS 0.0.0.0/0

VPC default security group
The VPC automatically uses the default security group. If you do not specify another security group when launching an instance, each EC2 instance launced in VPC is automatically associated with the security group named “launch-wizard-xx”. For example, the security group name of the first EC2 instance to launch is “launch-wizard-1”.

outpoud
Destination: 0.0.0.0/0
Protocol: all
Port: all
Range: Allow all outgoing IPv4 traffic

WhiteListing

Whitelisting is one of the methods used to filter email and websites.
While the blacklisting method creates a list of dangerous users and websites, the whitelisting method creates a list of targets for which safety has been confirmed and excludes others. While it is possible to cut off dangerous objects completely, the contents of the list is arbitrary and limited to a part of safe objects, and it has the disadvantage of losing the user’s convenience.

td agent execution log

$ /var/log/td-agent/td-agent.log
~ omission  ~
013-11-16 14:21:22 +0900 [info]: adding source type="forward"
2013-11-16 14:21:22 +0900 [info]: adding source type="http"
2013-11-16 14:21:22 +0900 [info]: adding source type="debug_agent"
2013-11-16 14:21:22 +0900 [info]: adding source type="tail"
2013-11-16 14:21:22 +0900 [warn]: 'pos_file PATH' parameter is not set to a 'tail' source.
2013-11-16 14:21:22 +0900 [warn]: this parameter is highly recommended to save the position to resume tailing.
2013-11-16 14:21:22 +0900 [info]: adding match pattern="td.*.*" type="tdlog"
2013-11-16 14:21:22 +0900 [info]: adding match pattern="debug.**" type="stdout"
2013-11-16 14:21:22 +0900 [info]: adding match pattern="mongo.**" type="mongo"
2013-11-16 14:21:22 +0900 [info]: adding match pattern="apache.access" type="file"
2013-11-16 14:21:22 +0900 [error]: unexpected error error_class=Mongo::ConnectionFailure error=#
  2013-11-16 14:21:22 +0900 [error]: /usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/mongo-1.8.6/lib/mongo/networking.rb:167:in `receive_header'
~ omission  ~

/var/log/lsyncd/lsyncd.status

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/lsyncd/lsyncd.status
Lsyncd status report at Tue Mar 12 00:44:51 2019

Sync1 source=/tmp/origin/
There are 0 delays
Excluding:
  nothing.


Inotify watching 1 directories
  1: /tmp/origin/

It doesn’t seem to be an lsync execution log.

What is /var/log/messages described?

The various logs output according to the system status are output to the following log files.

Log file name contents
/var/log/messages: general system related messages
/var/log/cron: messages about proccessing results that are executed periodically
/var/log/maillog: messages about mail
/var/log/spooler: printing messasges
/var/log/boot.log: Message about OS boot

Therefore, “messages” output general system related messages.

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/messages
May 29 08:22:59 localhost kernel: ata3.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
May 29 08:22:59 localhost kernel: ata3.00: failed command: FLUSH CACHE
May 29 08:22:59 localhost kernel: ata3.00: cmd e7/00:00:00:00:00/00:00:00:00:00/a0 tag 7
May 29 08:22:59 localhost kernel: res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
May 29 08:22:59 localhost kernel: ata3.00: status: { DRDY }
May 29 08:22:59 localhost kernel: ata3: hard resetting link
May 29 08:22:59 localhost kernel: ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
May 29 08:22:59 localhost kernel: ata3.00: configured for UDMA/133
May 29 08:22:59 localhost kernel: ata3.00: device reported invalid CHS sector 0
May 29 08:22:59 localhost kernel: ata3: EH complete
[vagrant@localhost ~]$ sudo tail -n 10 /var/log/messages-20190526
May 25 12:24:02 localhost /etc/init.d/kibana: Attempting ‘restart’ on kibana
May 25 12:24:02 localhost /etc/init.d/kibana: Killing kibana (pid 10114) with SIGTERM
May 25 12:24:02 localhost /etc/init.d/kibana: Waiting kibana (pid 10114) to die…
May 25 12:24:03 localhost /etc/init.d/kibana: Waiting kibana (pid 10114) to die…
May 25 12:24:03 localhost /etc/init.d/kibana: kibana stopped.
May 25 12:24:03 localhost /etc/init.d/kibana: kibana started
May 25 12:36:01 localhost dhclient[963]: DHCPREQUEST on eth0 to 10.0.2.2 port 67 (xid=0x5c1ebdd1)
May 25 12:36:01 localhost dhclient[963]: DHCPACK from 10.0.2.2 (xid=0x5c1ebdd1)
May 25 12:36:03 localhost dhclient[963]: bound to 10.0.2.15 — renewal in 39825 seconds.
May 26 03:27:07 localhost rsyslogd: [origin software=”rsyslogd” swVersion=”5.8.10″ x-pid=”1170″ x-info=”http://www.rsyslog.com”] rsyslogd was HUPed

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/secure
May 27 22:14:51 localhost sshd[12653]: pam_unix(sshd:session): session closed for user vagrant
May 29 08:31:19 localhost sshd[13390]: Accepted password for vagrant from 192.168.35.1 port 64022 ssh2
May 29 08:31:19 localhost sshd[13390]: pam_unix(sshd:session): session opened for user vagrant by (uid=0)
May 29 08:31:19 localhost sshd[13392]: subsystem request for sftp
May 29 08:50:13 localhost sshd[13400]: Accepted password for vagrant from 192.168.35.1 port 49488 ssh2
May 29 08:50:13 localhost sshd[13400]: pam_unix(sshd:session): session opened for user vagrant by (uid=0)
May 29 08:51:32 localhost sudo: vagrant : TTY=pts/0 ; PWD=/home/vagrant ; USER=root ; COMMAND=/usr/bin/tail -n 10 /var/log/messages
May 29 08:52:25 localhost sudo: vagrant : TTY=pts/0 ; PWD=/home/vagrant ; USER=root ; COMMAND=/usr/bin/tail -n 10 /var/log/messages-20190526
May 29 08:58:59 localhost sudo: vagrant : TTY=pts/0 ; PWD=/home/vagrant ; USER=root ; COMMAND=/usr/bin/tail -n /var/log/secure
May 29 08:59:23 localhost sudo: vagrant : TTY=pts/0 ; PWD=/home/vagrant ; USER=root ; COMMAND=/usr/bin/tail -n 10 /var/log/secure

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/cron
May 29 03:22:02 localhost anacron[13128]: Normal exit (1 job run)
May 29 04:01:01 localhost CROND[13336]: (root) CMD (run-parts /etc/cron.hourly)
May 29 04:01:01 localhost run-parts(/etc/cron.hourly)[13336]: starting 0anacron
May 29 04:01:01 localhost run-parts(/etc/cron.hourly)[13345]: finished 0anacron
May 29 06:01:02 localhost CROND[13347]: (root) CMD (run-parts /etc/cron.hourly)
May 29 06:01:02 localhost run-parts(/etc/cron.hourly)[13347]: starting 0anacron
May 29 06:01:02 localhost run-parts(/etc/cron.hourly)[13356]: finished 0anacron
May 29 07:01:02 localhost CROND[13372]: (root) CMD (run-parts /etc/cron.hourly)
May 29 07:01:03 localhost run-parts(/etc/cron.hourly)[13372]: starting 0anacron
May 29 07:01:03 localhost run-parts(/etc/cron.hourly)[13381]: finished 0anacron

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/maillog

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/spooler

[vagrant@localhost ~]$ sudo tail -n 10 /var/log/boot.log
Starting httpd: httpd: Could not reliably determine the server’s fully qualified domain name, using localhost.localdomain for ServerName
[ OK ]
Starting crond: [ OK ]
Starting Jenkins [ OK ]
May 19 07:16:49 localhost NET[12444]: /sbin/dhclient-script : updated /etc/resolv.conf
May 20 20:09:00 localhost NET[14514]: /sbin/dhclient-script : updated /etc/resolv.conf
May 22 08:31:26 localhost NET[14936]: /sbin/dhclient-script : updated /etc/resolv.conf
May 24 19:43:41 localhost NET[6409]: /sbin/dhclient-script : updated /etc/resolv.conf
May 26 13:02:39 localhost NET[12459]: /sbin/dhclient-script : updated /etc/resolv.conf
May 29 03:04:33 localhost NET[13192]: /sbin/dhclient-script : updated /etc/resolv.conf

Well, I absolutely understood that the output is completely different depending on the log file.

LogLevel’s Error Log

It is possible to specify up to 8 levels in the error log up to which level errors should be recorded. Set to “LogLevel” to specify.

Level: Meaning
emerg: Serious error that the server can not run.
alert: an error more serious than crit
crit: serious error
error: error
warn: warning
notice: notification message
info: server information
debug: information debugging

Is this basically something to do when look at “crit” and “error”?