Tomcat boot is very slow, connection to Oracle database failed, JDBC error log prompt connection reset, network interoperability between test hosts and database ports are normal

"Confirmation: At this time you may want to check/dev/random this device file. can be used cat/dev/random to see its content, if you find that he has not shown anything ﹝ may be garbled numbers and the like ﹞, that is, it is a problem. Through the cat/proc/cpuinfo |grep Rdrand can see if its CPU supports the DRNG feature, using hardware to increase the speed at which the entropy pool is produced (This doubt) "" Resolution: Increase/dev/The reason for the random entropy pool (recommended) problem is that because the entropy pool is not large enough, it is the most thorough way to increase it. We can do this through the software, the following is the software installation and configuration process. Installation Entropy service Yum install rng-Tools Start entropy Service Systemctl start rngd If your CPU doesn't support DRNG features or uses virtual machines like I do, you can use/dev/Unrandom to simulate. Look at the entropy pool size cat/proc/sys/kernel/random/Entropy_availvi/usr/lib/systemd/system/Rngd.service (or CP/usr/lib/systemd/system/rngd.service/etc/systemd/system; vim/etc/systemd/system/rngd.service) # # # #以下是编辑内容 Execstart=/sbin/rngd-f-r/dev/urandom### #systemctl Daemon-reloadsystemctl start rngdsystemctl enable Rngdsystemctl status Rngdcat/proc/sys/kernel/random/entropy_avail "" Reference to increase security at startup by randomly generating a key. /dev/random is a random function generator under Linux, and reading it is equivalent to generating random numbers. /dev/random will generate random numbers based on noise, which will clog if there is not enough noise. Linux is through i/O, keyboard terminals, memory usage, CPU utilization and other ways to collect noise, if the noise is not enough to generate a random number when it will be blocked. App service can be used/dev/urandom Replace/dev/random, in fact there is a third way-increase the entropy pool/dev/random. The problem is that because the entropy pool is not large enough, it is the most thorough way to increase it. By Cat/proc/sys/kernel/random/entropy_avail we can look at the current entropy pool size; we need to find a way to raise this value on the line. If your CPU has DRNG features, you can take advantage of the hardware to increase the speed of the entropy pool. by Cat/proc/cpuinfo | grep Rdrand can see if its CPU is supported, and generally Intel's CPU for the Ivy_bridge architecture is supported (i3, i5 need to be aware of that architecture, i7 and Xeon are basically supported), and AMD's CPUs are supported after 2015. (If you are a virtual machine you need to turn on additional parameters). If your hardware does not support it, it does not matter, we can let/dev/unrandom to do "entropy source". 】

Tomcat boot is very slow, connection to Oracle database failed, JDBC error log prompt connection reset, network interoperability between test hosts and database ports are normal