Victory goes to the player who makes the next-to-last mistake
February 15, 2018 Leave a comment
Add the following lines to the /etc/sysconfig/docker file and restart the docker
other_args="-H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock"
Restart Docker
service docker restart
Now check the docker API using the following command
curl host:4243/info
January 23, 2018 Leave a comment
This is a very common question that comes to our mind while setting up SSL in our applications. How to verify whether the key matches with the SSL certificate ?
A very easy way to verify that is given below.
We need to compare the modulus of the certificate against the modulus of the private key.
Execute the below command to get the modulus of a certificate.
openssl x509 -noout -modulus -in mycertificate.crt | openssl md5
This will generate the modulus something like e091f305089662689d62126d49910031
Execute the below command to get the modulus of a private key.
openssl rsa -noout -modulus -in mykey.key | openssl md5
This will generate the modulus of the private key. You should get the key modulus as same as certificate modulus above. i.e e091f305089662689d62126d49910031
If both the modulus are same, we can say that the certificate and the key are matching.
January 2, 2018 Leave a comment
The AWS account ID is a 12-digit number, such as 98765432109, that you use to construct Amazon Resource Names (ARNs). The AWS account ID distinguishes your resources from resources in other AWS accounts.
Sometimes we may have to get the aws account id. The following code snippet will help you to get the account id of the account corresponding to the given credentials. This code need access to AWS STS service.
November 15, 2017 Leave a comment
The installation of pycrypto package may fail with errors like
“error: no acceptable C compiler found in $PATH”
“RuntimeError: autoconf error”
“fatal error: Python.h: No such file or directory”
” #include “Python.h”
^
compilation terminated.
error: command ‘gcc’ failed with exit status 1″
The solution for this issue is to install the following dependent packages.
yum install gcc yum install gcc-c++ yum install python-devel pip install pycrypto
August 30, 2017 Leave a comment
To check the Java architecture whether it is 32 bit or 64 bit, the following commands will be helpful.
Execute the following commands in the command line and check the results
java -d32 -version java -d64 -version
If any of the above command is giving an error message similar to “Error: This Java instance does not support a xx-bit JVM.” If it is not supporting 32 bit, then we can say it is a 64 bit Java. If it is not supporting 64 bit, we can say it is a 32-bit Java. The screenshot of the same is attached below.
Hope this will help .. 🙂
August 7, 2017 Leave a comment
In an namenode HA enabled hadoop cluster, one of the namenodes will be active and the other will be standby. If you want to perform some operations on HDFS programmatically, some of the the libraries or packages need the details of active namenode (some of the packages in python need the details of active namenode, they will not support the nameservice). In this case, the easiest way to get the status is to issue a GET request similar to the one given below on each of the namenodes. This will help us to identify the status of each namenode.
GET REQUEST
curl 'http://namenode.1.host:50070/jmx?qry=Hadoop:service=NameNode,name=NameNodeStatus'
SAMPLE OUTPUT
{
"beans" : [ {
"name" : "Hadoop:service=NameNode,name=NameNodeStatus",
"modelerType" : "org.apache.hadoop.hdfs.server.namenode.NameNode",
"State" : "active",
"SecurityEnabled" : false,
"NNRole" : "NameNode",
"HostAndPort" : "namenode.1.host:8020",
"LastHATransitionTime" : 0
} ]
}
May 22, 2017 Leave a comment
I was getting the error “(13)Permission denied: access to /index.html denied” after deploying a static website in Apache webserver.
Solution:
Apache could not access those directories because of the SELinux security settings. Execute the below command
chcon -R -t httpd_sys_content_t
March 9, 2017 7 Comments
This code snippet will help you to get the list of all running EC2 instances across all regions in an AWS account. I have used python boto3 package for developing the code. This code will dynamically pick up all the aws ec2 regions. So the code will work perfectly without any modification even if a new region gets added to the AWS.
Note: Only the basic api calls just to list the instance details are mentioned in this program . Proper coding convention is not followed . 🙂
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